The Iron Age 1893-03-09: Vol 51

‘THE The Bogert Turret Engine Lathe. In the turret machine shown in the illus- tration, an attempt has been made to furnish machine shops with a tool that will materially reduce the time now taken in finishing work that is first chucked in one machine and then turned on an arbor in another, The headstock is shown equip- ped with a four-step cone for a 34 inch double belt, and with back gearing of a ratio of 12 to 1. It does not follow, how- ever, that this practice is recommended in all cases. Friction back gearing is more desirable when it is necessary, for instance, to tap or counter-bore a large hole and drill a small one in the same piece. In certain varieties of work it would even be a decided gain to have double friction back gearing, making possible four changes of spindle speed without shifting the belt on the cone. The size of the TuuRSDAY, Marcu 9, 1898. IRON AGE | operation, with its center 6 inches out from the axis of the turret. The most vital point in any turret machine, so far as accuracy is concerned, is the indexing. Very many otherwise carefully constructed turrets, after many months, or a few years’ severe service, get to have so much playin the lock bolt without any adequate pro- vision for taking it up that no two pieces will be turned out the same size with the same tools. This defect is here guarded against. The turret may be fed out toward the front of the lathe till its axis is 104 inches from the line of centers; hence apy surface that will swing clear of the bed may be turned with one and the same tool. The apron carries the feed gearing, which is made unusually powerful and dur- able, to permit the constant employment of cuts as heavy as the belt will drive. To this end the worm gears are made of phosphor-bronze, and the worms of hard Compound Expansion Engines.—IL. ( Conelusion.) These last results are, of course, hypo- thetical to the extent that they are based upon the assumed condition that the steam would impart and absorb heat as rapidly as the cast iron of cylinder, due to its degree of conductivity, the object being to ascertain the maximum possibilities of effect, in quantity and degree of heat, with reference to the cylinder only. This correctiop, however, will have no effect on the application of the results, as we shall see that the actual interchange of heat must be very far below the ascer- certained capacity of the iron cylinder; and the limit of effect, therefore, will be that due to the thermal properties of the volume of steam. We have in the 480 THE spindle is 34 inches, with a 1}3-inch hole, which can be increased to 2 inches by bor- ing. The material of which the spindle is made is very hard steel, and the boxes are lined with phosphorized babbitt metal. The lead screw, with its accompanying change gears, insures the proper starting of | dies and taps, as well as the cutting or chasing of threads of any pitch or di- ameter with single pointed tools. The carriage is 33 inches long, and, as will be noticed, extends well forward of the turret, so that the vertical component of strains on boring tools falls always within its supporting surfaces. The construction of the cross slide, which is patented, is novel in its essential details. The cross feed screw is completely protected from chips by a telescopic slide, which moves under the turret when the latter is fed toward the front of the carriage. When boring with heavy cuts the cross slide anchor and anchor bolts eliminate vibra- tion from the joint with the carriage. The turret is 14 inches in diameter, usually made six sided and usually bored for six 24 inch holes ; but the size and number of holes may be varied. The lock bolt of hardened steel slides vertically between hardened steel taper wedges and its conical end is firmly seated in a hardened steel bushing directly under the tool in BOGERT TURRET ENGINE steel. The engagement of the feeds is frictional, and therefore rapid. The half nuts open and close upon the lead screw with but a third of a revolution of the handle seen in a vertical position on the apron, The stop screws which control the movement of the cross-slide, as well as those governing the carriage feed, though not shown, are most important, as without adjustable stops the full measure of economy could not beobtained. In dupli- | cate work stops take the places of scales and calipers. The bed has tapered ends, is deeper in the middle than over the legs, which latter stand 224 inches in from each end. This detail of design was originated by Mr. Bogert in 1882, and developed in 1885 to substantially its present form. The cross braces between the shears of the bed are arranged on the well-known sys tem of bridge braces, each brace making an angle with the shears of about 45 de- grees. Instead of the plan view being a series of rectangles, it is composed of isos- celes triangles. By making the body of the bed consist of a number of vertical triangular cells any and all strains trans. mitted to the front shear are distributed over the braces to the back one. The lathe swings 20 inches, the bed is 8 feet 3 inches long, and the total weight 3600 pounds, F LATHE. -~= 6 1728 tao cubic inches 27273 cubic foot. The relative volume at 125 pounds is 219.6, and the weight per cubic foot one = cay 0.2842 pound. Then 0.27273 x 0.2842 = 0.0775 pound asthe weight of the quantity of steam in cylinder at point of cut-off. By Rankine’s formula the total quantity of heat contained in 1 pound of steam at 125 pounds (calculated from re- sults of experiments by Regnault) is found to be 11869, say 1187, heat units from water at 32°, as fullows: Units. 1. Required to raise temperature of water from 382° to 344.1° 2. To cvercome internal resistance vaporization 3. To overcome external resistance to OXPADSION. 2.6. wececcene eeeeeeese 4. Latent heat of vaporization (sum of SOME DE dedc caddeddcccspivenwanvedes 871.8 5. Total heat of vaporization above 32° Gout OF D GED) hac cccddsdweses ---- 1186.9 6. Normal temperature of steam at 125 pounds (absolute pressure).... ..... 344.1° The total heat, then, contained in the volume of steam is 1187 x 0.0775 = 91.9925 heat units, or but little more than twice the amount we have found the cylinder capable of absorbing for the 31.5° fall of temperature due to the final expansion. The quantity of heat actually lost by the 546 steam from decrease of temperature due to expansion only may be ascertained by comparing the respective amounts con- tained at-the two temperatures. These we find to be for 262 5°, 1162 units, and for 231°, 1152 units, the difference repre senting 31.5° loss of temperature, being but 10 units per pound, or 10 x 0.0775 pound = 0.775 unit for the actual volume, or 9775 _ 9.0084 = 7's per cent. of the 91.99 whole. This, it must be remembered, refers to the diflerence between the average of the 25 mean temperatures and that due to the mean steam pressure for the full stroke. The extreme difference between the latter and the initial temperature of the steam, 844°, will be 1187 — 1152 = 35 units x 0.0775 = 2.7125 units. This amount may be called the normal loss, as it is a theo- retically inevitable condition or effect of expansion as represented by the hypotheti. cal adibatic expansion curve, and to it must be added the total Joss from all other sources, Considering the effec; on the cylinder from the temperature due to mean variation, we have 0 on + 414 25 = at 0.0152°, and from the maximum variation 2.7125 414.25 = 0.05824°, the former 0.123 quantity, of course. being the cffective one. Comparing this with the effect from a difference of 184.8° between the initial and terminal temperatures of the steam, as previously noted, we find the quantity of heat will be 344° = 1187 (and 5 pounds terminal pressure) = 162.4° = 1131 = 56 units difference. Then 56 x 0.0775 =4 34,and 4 34 41425 = 0.133 0.0854°, the difference between which and the temperature due to mean variation being 0.0854° — 0.0152° = 0.0702°, or 0.0702 i 0.0152 _ 4.67, or 467 per cent. greater than the appar- ently true variation. On the theory, then, that saturated steam is at the point of both condensation and evaporation, the effect of the changes of temperature must cause a proportionate amount of condensation and re-evaporation, accompanied by a re- sultant increase of sensible heat in the for- mer and decrease in the latter, the effect of which will be referred to later. In the foregoing, the loss of heat by the cylinder has been considered only with relation to its effect on the volume of steam during expansion. There is, however, another important result, which is the ini- tial condensation, or that which occurs prior to cutting off. As the hottest part of the cylinder—i. ¢., that in- cluded between lines 1 and 2—must at all times have a temperature considerably below that of the steam entering from the boiler, there must necessarily be a very considerable amount of condensation, which primarily decreases the volume and necessitates a further supply from the boiler to compensate for the loss; and, secondarily, causes a very rapid increase in the amount of condensation (by reason of its high specific heat), from the fact that the water is in direct contact with the entering steam. The amount of initial condensation varies very widely in differ- ent engines; but, for the purpose of com- parieon, we may assume a given percentage, say for thesingle cylinder engine, and note the effect on the actual steam consump- tion. For instance, it is not uncommon for this loss to amount to from 10 to 30 per cent., and if we call it 20 per cent. our volume of steam admitted up to point of cut-off becomes—not 480 cubic inches, but 480 + 20 percent., or 576 cubic inches. Now, as to the effect of the secondary condensation, or that occurring during expansion. Owing to the give and. take transfer of heat between steam and cylin- der let us say that condensation is caused THE IRON AGE. by one-half of the exposed surfaces, while the other half, at the higher temperature, is causing revaporization of the film of condensed steam. Then, as the piston advances, the newly uncovered portion of cylinder surface, being cooler than the steam, will condense a certain portion of the latter, the tendency being to continue the effect until the equilibrium of tem- peratures had been effected, or, in other words, until tha: of the cylinder should be increased to a point corresponding with the reduced pressure of the steam. Of course the rapid movement of the piston renders the interval of exposure too short to admit of such equilibrium being actually established, and the effect of the tendency in that direction must be propor- tionate to the duration of exposure. But while this condensation is going on we have the opposite effect from the previ- ously exposed, and consequently hott:r, portions of the cylinder. Here the fall of pressure will allow of the revaporization of the water of condensation in the effort to restore the equilibrium between tem- perature and pressure. This evapora- tion, of course, absorbs or renders latent a certain amount of sensible heat, but it does not follow that it is taken from the steam. On the contrary, ow- ingto the high conductivity of the iron, and the actual contact between it and the water, the greater portion of heat ab- sorbed will be from the cylinder, and therefore its effect will not be felt until the succeeding stroke. If this be a correct statement, then we should find the gain in pressure from revaporization to be greater than the loss by condensation— that is, with relation to the effect on mean pressure for the full stroke—for the reason that the amount of surface exp sed to the higher temperature includes the areas of cylinder head and piston; while the cooler surface is only that of the internal periph- ery of the cylinder freshly exposed. That this is actually the fact appears to be dem- ovstrated by the comparison of the ex- pansion curve of the indicator card with that of the hypothetical diagram, as the former will show a pressure greater than that due to the mere effects of expansion. But while the greater mean effective press ure thus shown would apparently demon- strate a corresponding efficiency, it is not really the fact, as we must compare it, not with the indicated or nominal cut-off, but with the actual one, as represented by the additional supply of steam from the boiler necessary to make up for the heat previously abstracted from the cylinder, principally, by the revaporization of con. densation water. Thus, if we construct a diagram upon the indicator card, in which the point of cut-off is made to represent the actual volume of steam drawn from the boiler to fill our 480 cubic inches of space, we will have (for the assumed ini- tial condensation of 20 per cent.) 576 cubic inches, or a cut-off of 1.728 inches, instead of 1.44 inches. The theoreti cal curve for this cut off will be con siderably higher than that shown by the ‘indicator as representing the expansion due to the nominal cut-off and steam vol ume; and the difference between the two should represent the loss by cylinder con- densation. To make the comparison the 2,000 . 1 new expansion ratio will be- 576 ‘ = 20,83, the hyperbolic logarithm of which is 3.37; 1+ 337 20.83 the mean pressure, while that due to the nominal cutoff is 21.095 pounds, And 26.225 — 21.095 = 513 pounds, which, divided. by 21.095 = 0.243, or 243 per cent, less mean pressure than that actually due to the amount of steam drawn from the boiler. And this loss, it should be remembered, must occur then 125 x = 26.225 pounds as March 9, 1893 irrespective of any external loss of heat by the cylinder, although it may be greatly increased when’ the latter is considerable, from want of a proper jacket or non-con- ducting covering. Eliminating this portion of the subject, we may make the com- parison between the single and double cylinder engines entirely on the basis of cylinder condensation due to internal caus2s of variation in temperature. As in all calculations of this nature, the quantity of heat, or heat effect, is directly pro- portionate to the area and number of degrees difference in'temperature, it would. seem that a comparison of the products of the areas by their respective variations of temperature should give the correct rel- ative values of the two systems. For one single cylinder, then, we have in piston and cylinder head 6663 square inches ;, and in one twenty fifth of stroke 93 square inches, making a total of 760 square inches of surface causing initial condensa- tion. If we assume that the final revapor- ization and low terminal pressure have re- duced the surface of cylinder, say to the actual terminal temperature of the steam, although it will not be accurate as rep- resenting the actual loss, it will appear correct as the basis of comparison. Then 344° — 162.4° = 181.6°, and 181.6° x 760 square inches = 138,016. For the com- pound engine, we have in the small cylinder 100 + 100 square inches in p'ston and cylinder head, and 170 square inches for one-fifth of cylinder area, making 370 square inches. The difference of tempera- ture is 344° — 240° = 104 which x 370 = 38,480. In the large cylinder 500 + 500 + 879 = 1379- square inches, whica x (240° — 162 4°) = 77 60 = 107,010. The sum of these two quantities, 38,480 + 107,010, = 145,490, appears to indicate a loss greater than that of the single cylinder, but we must take into consideration the fact that, while all of the revaporization in the latter, occurring after release, passes into the condenser without useful effect, that in the small cylinder, at the terminal of 25 pounds, becomes effective in the large one, and should therefore be deducted from the aggregate, making 107,010 as the loss by compoundengine. Tae difference between this amount and the loss by single cylinder will be 1,008 0.225, or 224, 138,016 per cent., saving by the former in the item of cylinder condensation; i. ¢., if the net loss by the single cylinder be 20 per cent. of the initial volume, that by the compound engine will be but 774 per cent. of 20 per cent., or 154 per cent., net loss, aS representing the initial condensa- tion. Then, as by previous calculation of percentage of loss in mean pressure, due to the actual volume of steam drawn from 100 x 24 7 480 + (480 x 0.155) — 4.275 as the new expansion rat:o—he hy- perbolic logarithm being 14663. Then 1+ 1 4663 On ~*~ have found in the value of C for five ex- pansions (Part I) a mean pressure of 65.24 pounds, the difference—6.9 pounds =: 0.1057, or 10.57 per cent.—represents the deficiency in mean pressure as compared with that due to the actual steam con- sumption. The saving, then, by com- pounding appears from our calculation to. 20 — 154 20 tirely on the basis of cylinder condensa- tion, as assumed at 20 per cent. of the: nominal volume of steam in single cylin- der eagine. As to the effec: of external sources of heat loss, it seems hardly neces- sary to go into detailed calculations, as. with equally efficient non-conducting cov- erings (which are applicable to both types. of engines) the only difference in effect: boiler, we have = 72.14, and as we be as = 224 per cent., and en- March 9, 1893 will be directly proportionate to the dif- ference of external areas. In the foregoing, of course, the object has been not to show the actual amount of saving by the com- pound system, but rather to point out some of the erroneous methods of calcula- tion, and to suggest a course of investiga- tion apparently in the right direction. From the absence of any accepted ex- planation of the phenomena involved in compound expansion it is reasonable to consider the question as one still to be solved, and it is hardly probable that this can be convincifgly done without the most exhaustive experimental investigation on the scale of full practical operations. The expense necessarily involved in such tests places the subject beyond the reach of individual effort, which may probably account for our lack of absolute informa- UOT * TN HYDRAULIC POWER PLANT THE IRON AGE, Hydraulic Power Plant of United States Coast-Defense Vessel ‘‘ Mon- terey.” The machinery and appliances on this vessel that are worked by hydraulic power are the engines for turning the forward and the after turrets, the elevating gear of the guns contained in the turrets, the steering engines, and the opening and closing gear of the battle hatches. The pumps for furnishing the water under pressure are two sets of horizontal pumps, one for the forward and one for the after turret, and one vertical three cyl- inder pump for the steering gear and battle hatches. The plant for the forward turret, which contains two 12-inch breech: loading rifled FOR U. S. COAST-DEFENSE tion, beyond the mere comparison of fuel | guns, consists of two independent pumps consumption, as shown by the indicated | discharging into the same air chamber power of engines of the two types. }and having steam cylinders 26 inches | diameter and 27 inches stroke. The diam- I The New York Supreme Court has re- cently, following precedent, decided that | commercial travelers’ trunks, when con- | taining samples, are not baggage for | which the railway company is liable. The | principle is that the railway agrees only to | carry the traveler and his clothing. It is| argued that if any other rule were adopted it would be possible for a passenger to in- | sist upon the company taking his whole furniture or half his stock of merchandise | in the baggage car, in order that the mer- chandise might obtain as quick transport as he himself expects. Atthe same time, every facility not inconsistent with their | duty ought to be granted by the railways | to such regular patrons as the salesmen have proved themselves to be. A regular line of steamers from New York to the river Plate will make de-| partures on the 25th of each month for | Montevideo, Buenos Ayres and Rosario, | | so that merchants can depend on having | their goods forwarded. |four groups of four valves each. |eter of the water piston is 10 inches and its stroke is the same as that of the steam piston. The steam cylinders, which are fitted with an easily removed liner, are made of cast iron and are provided with the Dow valve gear. The water ends of the pumps are made of phosphor bronze, the water cylinders being without a work- ‘ing liner. The suction and delivery valves, which are arranged in four pots, consist of The valve bodies, which are of phosphor | bronze, are recessed for hard rubber faces. They are guided by a spindle on their | backs and are seated by springs aided by hydraulic pressure. The steam and water ends of the pumps are bound together by four steel rods flanged at each end, the flanges being bolted to faces on the cast- ings. The water piston is packed with square flax packing. All water valves in connection with the pumps are straightway. The conditions attending the use of hy- draulic power on board ship do not per- 547 In order to preserve a constant water pressure in the system the following device is used, Fig. 5: A chamber of cast iron placed between the pumps is fit- ted with an internal cylinder in which a piston works. This piston is connected by means of its rod and levers with a throttle valve common to the two pumps. The space in the cylinder above the piston is connected by means of a pipe with the discharge pipe of the pumps; the space below the piston is in communica- tion with a charging machine or air com- pressor situated in the starboard engine room. Variations in pressure between that given by the charging machine and that produced by the pumps cause movements of the piston and adjustments of the throttle and speed of pumps until like pressures are produced. VESSEL “ MONTEREY.” When once the air pressure in the air ac- cumulator, as it may be called, has been raised by the charging machine to the re- quired point, the loss of pressure from leakage is very little, as the arrangement becomes practically automatic. The accompanying perspective view and drawings show the pumps for the after turrets, which contains two 10-inch breech- loading rifles. They are similar to those described for the forward turret, but are smaller in size. The steam ends of these pumps were built by the Dow Company of San Fran- cisco, and the water ends by the Union Iron Works of the same place. The pumping engine for furnishing water to the steering engines and for operating the gear for the battle hatches consists of three vertical direct-acting plunger pumps, each operated by an 8 x 8 steam cylinder. The | pump plungers are continuations of the steam piston rods. The pumps are con- nected through cross heads and connecting rods with a crank shaft, the cranks being 120° apart. The valve, a common D slide, is worked from this shaft by the usual eccentrics and rods. A governor similar in principle to that already de- ‘mit the use of a weighted accumulator. | scribed for the turret pumps operates a 548 THE IRON AGE. March 9, 1898 throttle common to all three steam cylin- ders. The three systems are cross connected, so that when needed any pumps can be put on any of the work. Tanks are fitted for holding the supply of fresh water used in the systems, the exhaust from the different hydraulic machines leading back to these tanks. HYDRAULIC POWER The’ pressures used in operating the machinery are from 400 to 700 pounds per square inch, The plan works well in actual use, the regulation being clese and efticient and to all purposes automatic. a Forty men from Pittsburgh and vicinity are about to form a co-operative commu- nity at a well-known resort in the mount- ains of Colorado. Manufactories are to be erected by some, while others engage in farming and mercantile business, The Central Universal Mill. During a recent visit to Harrisburg an opportunity was afforded to inspect one of the latest additions to plant in Central Pennsylvania, the large new universal plate mill of that old established concern, the Central Iron Works. A thoroughly modern plant, the mill may be regarded as DECK CONNECTED TO AiR. COMPRESSOR Fig. 3.—Plan. PLANT FOR U. S. COAST-DEFENSE being in many respects a model. It is housed in a fine new iron building, 394 feet by 90 feet, the iron work of which was built by the Pennsylvania Steel Com- pany. The train, which was built after the designs of Henry Aiken of Pittsburgh by the A. Garrison Foundry Company of Pittsburgh, has 25-inch horizontal rolls and 16-inch vertical rolls, driven by a pair of fine 30 x 60 inch engines, built by Tod & Co. of Youngstown, Ohio. The spur gearing driving the vertical rolls is placed within the housings, which are of excep- tional weight. The screws of the hori- zontal rolls are operated by rack and pinion through hydraulic cylinders, while the vertical rolls are operated by hand, the gearing on both sides being coupled. The maximum width which the train is capable of rolling is 42 inches. The roll tables, front and back, are 50 feet long, while the cooling table has a total length VESSEL ‘“ MONTEREY.” of 80 feet. The plate is moved sideways from the cooling table by a chain rig, and aturning gear is interposed between it and the shearing table, so that both sides of the plate can be inspected. The shear- ing is done by a hydraulic shear, which was built by the Hydraulic Machine Com- pany of Pittsburgh, who also built the tables, while the hydraulic pump was sup- plied by Wilson & Snyder of Pittsburgh. The whole of the train, engines, tables and shipping department, with its de- pressed track, are controlled by a 20-ton March 9, 1898 THE IRON AGE. 549 Morgan electric traveling crane with 65- foot span. The iron or steel slabs are picked up by a smaller electric crane traversing the lower end of the building. Near it stand two groups of two Siemens regenerative heating furnaces, with three working doors, handled very neatly from one point by a hydraulic gear. The slabs are at present handled by a five-motor electric overhead traveling charging machine. Gas is furnished to the heating furnaces in this mill, and to one new furnace in the old plate mill, by a battery of ten Wellman gas as two being in reserve. The iler plant consists of three fine batteries of boilers, two of three and one of four, errected by the Harrisburg Foundry & Machine Company. Locke regulator. The auxiliary plant embraces a tandem compound engine built by the Harrisburg Foundry & Machine Company, driving a| Thomson- Houston 50-horse generator for the electric motor plant and two 50-light dynamos. = Sele | 4 oe a . { CONNECTED TO FORWARD TURRET GEAR Fig. 4.—Sectional End Elevation. HYDRAULIC POWER An exceptionally well lighted testing room contains an Olsen machine, driven by motor, and will soon be equipped with lathes, &c. The plant, which was started in April last, has now been running for some months, its capacity being 100 tons per day. The officers of the Central Iron Works are Charles L. Bailey, president; Edward Bailey, vice-president; G. M. McCauley, secretary and treasurer, and J. N. Binnix, superintendent. ———— I The commercial value as well as the strategical importance of the Hawaiian Islands is the subject of discourse by Captain Mahan, U. 8. N., who speaks of their commanding position with reference to the future outlet of the Nicaragua Canal on the Pacific, and says: ‘‘ The islands form the center of a circle, of which the radius extends from Honolulu to San Francisco, and upon the periphery of which are found the other chief archipelagoes of the Pacific, the Gilbert, Marshall, Samoan, Society and Marquesas groups. They would form a most valuable link in the chain of naval stations between British Columbia on the one hand and Eastern Australia and New Zealand on the other, but the claim of the United States to them, both commercially and geographically, is much stronger than that of Great Britain.” SS eI The New Shipping Bounty Law of France. An article which appeared in The Iron Age of October 13, 1892, dealt at some length with the French shipping bounty system adopted in 1881. A summary of the provisions of the law authorizing the payment of bounties was given, the results of the practical operation of the system as illustrated by statistics were considered, It is equipped with a | and the chief features of plans proposed for adoption in a new law were noted. | It may be recalled that the law of 1881 provided for the payment of bounties both for ship construction and for over-sea or | long-distance navigation, that the con- struction bounties were authorized with- made by the Chamber of Deputies in the measure as submitted to it. The most important modification was the striking out of all provisions for the payment of any bounties for voyages made by merchant vessels procured abroad hereafter for em- ployment under the French flag. The committee had reported provisions cover- ing the payment of navigation bounties to such vessels at one-half the rates payable to French-built vessels. Another note- worthy change was the reduction of the construction bounty for iron or steel ves- sels to a figure far below that recommended by the committee and but slightly in ex- ao the rate heretofore paid under the old law. The new law is to remain in force for ten years. Like the old one it provides for the payment of construction bounties and navigation bounties. New features are introduced, following the suggestions of the committee, in extending a naviga- tion bounty to vessels engaged in European commerce other than local French traffic, out apy limitation as to the length of|and in providing that vessels built in PLANT FOR U. Ss. time the provision establishing them should continue in force, and that the navigation bounties were to be paid for a period of ten years only. So far as they applied to French-built vessels the navigation bounties have been continued in operation since 1891 by special enactment from time to time, owing to delay in arriving at a final de- cision as to the details of a new and com- prehensive echeme having in view the formulation of a definite policy to be oper- ative fora further term of years. The exhaustive inquiries and painstak- ing labors of a committee specially charged with the consideration of the matter re- sulted in the preparation of an elaborate project, which in its original form met with considerable opposition, and a com promise measure was finally submitted to the Chamber of Deputies last summer. The article to which reference has been made as having appeared in The Iron Age noted the salient features of this measure, which forms the basis of a new law re- cently adopted by large majorities in both the Chamber and the Senate. This decisive action was not taken, how- | ever, until material changes had been COAST-DEFENSE VESSEL Fig. 5.—Section through Air Cylinder and Controlling Gear. ‘* MONTEREY.” France at any time during the next ten years may continue to earn navigation bounties for ten years from date of regis- try. Thus there may be cases in which this feature of the law will not cease to be operative until 20 years from the present time. The construction bounties authorized by the new law for vesse!s built in France during the next ten years are as follows: Per ton- Gross measure- ment. For iron or steel vessels, steam or sail. ..$12.54 For wooden vessels of 150 tons and Wa 5 ioc wnt dostuncetesencesameeet 7 For wooden vessels of less than 150 tons. 5.79 For changes having the result of in- creasing the measurement of a vessel a bounty is to be paid, calculated for such increase on the same scale as the allow- ance for a new vessel. For engines and boilers, including aux- iliary machinery, a bounty of $2.90 per 100 kg. (equal to $1.314 per 100 pounds) is pro- vided. Replacing old boilers carries an allowance at the same rate for the weight of the new boilers, when of French make. the new law can be earned only by vessels built in France or by those of foreign origin admitted to French registry prior to January 1, 18938. They cannot be paid to vessels engaged in the fisheries nor to those employed in regular service on subsidized routes nor to pleasure craft. These boun- ties, fixed at different specified rates, are payable, subject to the restrictions noted, to vessels making over-sea voyages and to those engaged in European commerce other than the French domestic carrying trade. A minimum distance of 120 miles between a French and a foreign port is requisite, and a certain proportion of the cargo must be unloaded in the case of European ports. The navigation bounties are fixed at so much per ton, gross measurement, instead of net measurement-as under the old law, for every 1000 miles run. The rates per ton under the new law for each 1000 miles run, in the case of vessels making over-sea voyages, are as follows, subject to an annual decrease, reckoned from the date of building: For steamers built in France, and for such foreign built steamers as were ad- mitted to French registry prior to 1881, the standard or full rate, to be diminished secording to the age of the steamers, is 21.2 cents. For foreign-built steamers admitted to French registry during the operation of the old law, but prior to January 1, 1893, one-half the foregoing standard rate, but the full amount of an nual decrease is to be applied to the half rate. For sailing vessels built in France, ard for such foreign-built sailing vessels as were admitted to French registry prior to 1881, the standard or full rate, to be dimin- ished according to the age of the vessel, is 32.8 cents. For foreign-built sailing vessels admitted to French registry during the operation of the old law, but prior to January 1, 1893, one-half the foregoing standard rate, but the full amount of an- nual decrease is to be applied to the half rate. The rates per ton under the new law for each 1000 miles run, in the case of vessels engaged in European commerce and enti- tled to bounty, are as follows, subject to an annual decrease, reckoned from the date of building: For steamers built in France, and for such foreign-built steamers as were ad- mitted to French registry prior to January 1, 1893, the standard rate, to be dimin- ished according to the age of the steamer, is two-thirds the full rate for new French- built steamers making over-sea voyages, or 14.1 cents. For sailing vessels built in France, and for such foreign-built sailing vessels as were admitted to French registry prior to January 1, 1893, the standard rate, to be diminished according to the age of the vessel, is two-thirds the full rate for new French-built sailing vessels making over- sea voyages, or 21.9 cents. To obtain the rate of navigation bounty for any particular vessel there is deducted from the standard full rate or half rate applicable to such vessel a certain amount for every year that has elapsed since the vessel was built. This annual decrease is: For wooden sailing vessels, 1.54 cents; for wooden steamers, 1.16 cents; for iron or steel sailing vessels, 116 cents, and for iron or steel steamers 0.77 cent. From the gross amount of every con- struction or navigation bounty, 4 per cent. is to be retained for the relief of ship- wrecked French mariners and their fami- lies and also for the purpose of aiding in the establishment in French ports of insti- tutions intended to conduce to the welfare of the maritime population. a P Manufacturers in Maine have combined to utilize the water power of the Kennebec River by building reservoirs, Tbe navigation bounties authorized by THE IRON AGE. A Compound Air Compressor. The increasing use of compressed air at high pressures renders the subject of im- provements in compressors one of consid- erable importance. That there is room for improvement, even in the best types of this class of machinery, is shown by the comparatively large percentage of loss in converting steam power into useful effect through the medium of compressed air. The loss of efficiency must in any case be considerable, owing to the physi- cal phenomena of compression—judging, at least, from our present knowledge of the subject—and therefore it becomes all the more important that the mechanical defects of the compressor be minimized. This fact is fully realized by the builders of high-class compression machinery; aod though the subject has received the atten- tion of the best engineering talent, the effort has been almost exclusively in con- nection with the ordinary moderate press- ures, ranging from 50 to 100 pounds, While in the past, the use of what may be properly termed high pressures has been contined to exceptional cases and the ma- chinery for the purpose considered as ‘* special,” the requirements of the present or near future would appear to suggest that it should be recognized as a distinct type and of sufticient importance to merit fully as much attention as that designed to produce lower pressures. E£xperience has long since demonstrated the impracti: cability of simple or direct compression to pressures much in excess of 100 pounds, that is, from the normal to ultimate pressure in asingle cylinder at one operation, and, therefore, recourse was had to the use of two cylinders and compound compression. In the first cylinder the air is compressed from atmospheric to about one half of the desired ultimate pressure and discharged. either directly or through an intervening reservoir, into the second, smaller, cylin- der, where the final compression is accom- plished. By such arrangement pressures up to 500 or 600 pounds are easily attained, and when the requirements are greatly in excess of that limit they may be readily met by still further compounding, and using triple or quadruple compression by means of three or four cylinders. There is, however, an acknowledged objection to ths arrangement in the unavoidable complication and multiplication of parts necessary to provide each cylinder with its separate valves, piston, and power and pipe connections. Not only is the cost of the machine proportionately increased, but its efficiency is necessarily diminished by reason of the increase of working friction, loss from leakage, and multiplication of piston and valve clearances. The accom- plishment of this compound compression, whether double, triple or quadruple, in a single cylinder is the object for which the air compressor. herewith illustrated, was designed by B. Frank Teal, 442 South Campbell avenue, Chicago. The novel features of the device are embodied in the air cylinder exclusively (a sectional draw- ing of which is here presented) as the methods of applying the steam water or belt power are made conformable to the | best modern practice and may be modified to any extent to suit the particular re- quirements of different applications. The illustration shows a vertical section of air cylinder with its piston, valves, &e. <A is the cylinder formed with double walls, and the intermediate space r serving as a water jacket. The water circulation is constant, entering at bot- tom and discharging at top through pipes not shown. A’ is the lower cyl- inder head, in which are located the suction valves 4, g, which open inward, and are of the ordinary construction, ex- cept that the guide wings are set at an angle, instead of being parallel with axis, March 9, 1898 as incorrectly shown—the object being to cause the valves to turn slightly for each stroke, in order that they shall seat at a new point with relation to the seat, and thereby wear uniformly. The piston is composed of the head and the large trunk B, the latter passing through the upper head A’®. The space C con- tained between the trunk and cylinder, forms an annular chamber, which com- municates with the cylinder space be- low the piston head through ducts, h, chambers, i, and valves, g’. The bronze ring n serves as a guide bearing for the trunk to relieve wear on the stuffing box. It is made a driving fit in the cylinder, and bears closely against the internal flange. The discharge valve m is of pe- culiar construction, having at its inner end an air-tight piston, of same area as the valve proper. The spiral spring is made of only sufficient tension to keep the valve firmly to its seat. The object of this arrangement is to obviate the necessity for increasing pressure in the cylinder, to overcome that on back of valve, owing to the greater area of the upper as compared with the lower side. This feature, which at ordinary pressures may be neglected, at high pressures becomes of considerable importance, as may be seen. If the valve opening have a diameter of 3 inches and width of seat of 2 inch, the difference be- tween the upper and lower areas will be 11 —7 = 4 square inches, or about 57 per cent. Ata receiver pressure of 500 pounds, the total pressure on back of valve will be 5500 pounds, and will require in the cyl- inder a pressure of — = 786 pounds, ‘ nearly, acting on lower side of valve to cause it to open for discharge. By means of the piston, the valve is caused to open as soon as the cylinder pressure shall have reached that of the receiver, as the resist- ance of the spring is inappreciable. The valve seat is removable for convenience of fitting the valve, and is held in place by the ribs projecting inward from cover. The opening to the discharge pipe, com- municating with the receiver, is shown at k. There are two important features not shown in engraving, {n the inner surface of lower cylinder head A’, there is an annular channel formed in the solid metal surrounding the piston-rod stuffing box, which channel is covered by a ring of thin metal, in which are numerous fine perfora- tions to form a sprinkling or, more cor- rectly, a spraying plate. Also in the upper ring n a channel is turned in the outside periphery, near the bottom edge, and cim- ilar holes drilled through from the bot- tom. These channels are independently connected, by means of extra strong wrought-iron pipes, to the two small sin- gle acting force pumps attached to bed plate of the engine and deriving their motion from crank on the main shaft. At each stroke of the engine, the pump con- nected with the end of the air cylinder in which compression is taking place, is forc- ing cold water into the cylinder, against the increasing air pressure, while the other pump is working on the suction stroke. The piston and trunk packing is of the ordinary form of leather cups—that of the piston being double and separated by a thin metal ring, which is turned at its outer periphery to fit the rounded corner of the cups and thereby prevents their be- ing forced out of shape by the heavy press- ure. When the desired pressure is so great as to require triple compression, the trunk B is provided with a head at the top, and forms a reservoir into which the discharge from the second compression is forced. The valve m is omitted entirely, and is substituted by two or more smaller valves, similar to those shown at q’, 4’, and located near the latter, in the piston head. The communication between the annular cylinder space C and the interior March 9, 1893 THE IRON AGE. of the trunk B* is by means of small ducts, like n, through the valves described. Attached to the upper head of the trunk, and projecting inwardly into the space B’, is acylinder of small diameter, hav- ing at its lower end a single inlet valve. In this cylinder is a hollow plunger or trunk piston, similar to that in the large ‘cylinder, and of like proportion of areas. {It also is provided at its lower end with the valves gg close, and the contained air is compressed until the pressure is suffi- cient to raise the piston-head valves 4’ q’, when it is discharged into the annular space C. At the next upward stroke, while the cylinder is again filling with free air, the partially compressed volume in C receives its final compression, and is dis- charged through the valve m As before stated, the water from the small force Pr eenccaneeseens ese COMPOUND AIR a single valve.™ This plunger is, of course, | stationary, and‘is carried by standards and cross beam, attached to main cylinder. The discharge connection between com- pressor and main air receiver is made by piping from the top of the stationary plunger. The operation of the machine is so ob | vious that only the briefest description is needed, During the upward stroke of the piston, the suction valves g 4 ‘open and admit air to the full volume of the cylin- der. As soon as the motion is reversed COMPRESSOR.—SECTION THROUGH AIR CYLINDER. pumps is sprayed against the air during the compression stroke, and absorbs a very large percentage of the heat of compres- sion. This, in connection with water in the eylinder jacket, serves not only to prevent overheating of the cylinder and working parts, but also to greatly increase the capacity and economy of the machine, by preventing the expansion of the volume of air and a corresponding pressure, which weuld become a dead loss as soon as the 551 complete displacement of the air at each stroke, as, no matter to how small a per- centage the clearances of valves and piston may be reduced, the effect, under high pressures, must involve a very consider- able loss unless some means of prevention be used. The surplus of water is dis- charged with the air at each stroke, and seals the valves against air leakage back to the cylinder. In a horizontal compressor the piston rod is dispensed with, and the trunk, be- ing reversed, is used to compensate for the vibration of the connecting rod, which connects directly with the wrist pin car- ried by jaws bolted to the pistou head. This may also be done in the vertical ma- chine, though there are serious objections to the plan, and the disadvantages would more than counterbalance the gain from its use. (To be continued.) I A New Mitrailleuse for Cavalry. A form of mitrailleuse which, owing to its lightness, is said to be peculiarly well adapted for service involving rapid move- ment has been devised recently by a French artillery officer, and having been submitted to the Minister of War, is now being sub- jected to experimental tests. This arm is intended primarily for the use of cavalry or for employment in mountainous dis- tricts where the transportation of heavier pieces of artillery might be difficult. The inventor claims that his weapon will not impede the movements of cavalry, as each mitrailleuse complete with 2000 rounds of ammunition can be eesily carried py one horse. As a mountain gun the piece can be car- ried by one man on a frame work of wood or metal forming a sort of hod, which is so constructed as to serve as a mount for the gun in action. It is asserted that one artillery man or properly trained cavalry or infantry soldier can mount the gun ready for use almost instantly and that its service requires but one man. The new mitrailleuse can fire 600 small- caliber projectiles per minute, equaling the performance of 25 or 30 men, and this can be maintained for a considerable time. Officers who have witnessed the trials executed by direction of the French authorities express the opinion that the use of the new weapon would be extremely advantageous in cases where a cavalry force was suddenly required to hold or attack a position against infantry. Should further tests continue to prove satisfactory the issve of some of these guns to certain cav- alry corps is said to be contemplated, in order that they may be subjected to trial under ordinary service conditions. a Comptroller Myers of New York was disappointed last week when he learned that his proposed loan of $1,000,000 was sub- scribed for only in part and that none of the offerings were for more than par. It is said that investors are a little afraid that new schemes involving $5,000,000 for a gentleman’s driving boulevard, $10,000,000 or $12,000,000 for a new city building, nobody knows how many millions for a rapid transit system, and $7,000,000 or $8,000,000 for the completion of a water system that would supply a city of 10,000,000 inhabitants, will overburden the city, and, toa certain extent, the credit of the city is affected. At a grand union meeting of the Broth- erhood of Locomotive Engineers in the Northwest, held at Ironton, Mo., Chief Arthur made the closing address, and spoke enthusiastically of the advancement in the condition of the locomotive engi- temperature became reduced to the normal | neers brought about by the work of the degree. The injected water also insures Brotherhocd. 552 WORLD'S FAIR NOTES. Description of Machinery Hall. In exterior design, says the Chicago Herald, Machinery Hall is more than merely grand and imposing. It approaches the gorgeous in architecture, and the gen- eral effect of the towers and exterior orna- mentation is magnificent. The main build- ing is 850 feet long and 350 feet broad. The interior looks like three large rail- road train houses side by side, each spanned by arched iron trusses 125 feet long and 50 feet on centers. Outside of the main hall there is an immense annex, opening directly into the main building. In each of the four corners of the main | building is a domed pavilion with a grand staircase. The main entrances are on the | north and east sides, with many other en- trances along the sides and ends of the) main hall and annex. The power plant is | on the south of the main building, in a one-story structure which runs the whole length of the building. The ornamental work of the exterior shows the purpose of the building, the statues and portraits | representing mechanical forces or great | inventors. Exhibits are being daily installed in Machinery Hall. Three avenues or aisles run the entire length of the main building and annexes, the center one 25 feet wide and the sides each 15 feet wide. Tracks of auxiliary railroads are connected with these aisles and heavy machi