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The calculated discharge of pumps By gauge on force pipe...... 135.6931 By difference between center of

per revolution of engine has been stated gauge on force pipe and mean

as 155,693 gallons.
level of water in river during
trial....

29.055

The water weighed to the boilers dur. By friction head suction pipe... 2.3806

ing the whole trial was 68238 pounds, By friction head force pipe.. .161 from which is deducted the following By friction head 20" elbow in

quantities: force pipe...

.0155 By allowance for resistance of

Drawn off to calorimeter...... 168.875 water passages in pumps....

2.3

Leakage between weighing tank
and boilers...

50.322 Total head....

169.6052

Entrained in the'steam, 4.7489 per
cent...

3230.145 The calculated discharge of pumps

Total deduction.......... 3449.342 per revolution of engine has been stated as 155,503 gallons.

and net steam delivered to the engine The water weighed to the boilers dur- becomes 64788.658 pounds corresponding the whole trial was 65228 pounds, ing to an expenditure of coal under the from which is deducted the following terms of the contract, of 7198.74 pounds. quantities:

From which I estimate the duty of

engine No. 2 as Drawn off to calorimeter.... 172.125 Leakage between weighing tank

155.693 x 27485 X 8.34 x 178.8921 and boilers....

50.322

71.9874 Entrained in the steam, 1.93 per cent.... 1254.607

=88,688,866.4. Total deduction.......... 1477.054

In regard to the capacity guaranteed

for the engines, I am inclined to believe, and net steam delivered to the engine in view of the stipulated dimensions of becomes 63750.946 pounds, correspond- pumps and piston speed, that the incoring to an expenditure of 7083.44 pounds poration in the contract of four millions of coal, upon the evaporation stipulated (4,000,000) gallons capacity was unintenin the contract.

tional, as the prescribed data of the conFrom which I estimate the duty of tract prohibits this discharge. engine No. 1 as

You will observe that both engines

have exceeded the contract duty, one by 155.503 X 26370 X 8.34 x 169.6052

nearly two millions, and the other by 70.8344

more than eight and one-half millions. =81,885,917.12.

In the general report, which I shall The duty trial of engine No. 2 com- submit at an early date, will be given all menced at 10.45 A. M., January 29th, and the data taken during the trials, together terminated at 10.45 a. M., January 30th. with an inquiry into the preciee perform

ance of the engine, as developed from The counter reading at beginning of the indicator diagrams. trial was.

501 And at end of trial..

27986 Difference-revolutions...... 27485 A PULVERULENT lubricating material for

axles, shafts, &c., is prepared by Herr The head pumped against in feet was Drechsler, of Dresden, thus: The finest By gauge on force pipe....... 141.372

graphite powder is worked up thoroughBy difference between center of

ly with egg-white, or yellow, or both, to gauge on force pipe and mean

a firm dough, which, in a metallic vessel, level of water in river during

is kept in a vessel of boiling water, till trial....

32.437 By friction head suction pipe..

the egg-white and yellow are fully coagu

2.5925 By friction head force pipe.

.1737

lated. The mass is then dried at 90° C., By friction head 20” elbow in force

so thoroughly, that it can be bruised or pipe....

.0169 stamped to powder. This powder is apBy allowance for resistance of water passages in pumps

plied to a slowly-revolving axle or shaft, 2.3

till axle and bush take the peculiar dark Total head......

178.8921 shine of graphite.

STREET CLEANSING IN PARIS.

By M. VAISSIERE.

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From Foreign Abstracts of Institution of Civil Engineers. The cleansing of the public thorough-, ways employed when it is desired to fares in Paris, formerly undertaken by destroy the germs of putrid fermentathe Prefect of Police, is now a function of tion. It is used at a strength of about the Prefect of the Seine. The staff con- to, say a gallon of the acid to 40 gallons sists of two chief engineers, one for each of water. At strengths of

1οο and group of arrondissements, one group be- it gives good results for watering once ing subdivided into three sections, each or twice a week in summer those parts under the charge of an executive engineer; of the Halles Centrales liable to infecand the other into five sections, similarly tion. It is even used as low as Totoy for supervised. These sectional engineers watering streets and gutters. Hydrohave under them fifty-one superintend- chloric acid is applied to urinals and ents and sixty-one overseers, whose em- slaughterhouses. In places much enployment imposes upon the wunicipal crusted with tartar it is used at a budget an annual cost of 260,000 francs. strength of $. Lowered to it cleans The scavenging plant is kept in a central smooth walls and flags efficiently. depot, where materials of every descrip- ordinary rinsings a strength of suffition are stored and classified, for ordi- ces. It leaves a disagreeable odor benary and extraordinary service, when hind, which is, however, quickly dissisnow and ice render additional assist- pated. Mirbanic acid (nitro-benzide) is ants necessary.

more energetic than the foregoing, but The depots contain supplies of chlor- it produces a disagreeable smell of bitide of lime, sulphate of zinc, sulphate of ter almonds, and leaves a white film which iron, and carbolic acid, as disinfectants; has to be washed off. It is used at the and hydrochloric acid, nitro-benzide same strengths as hydrochloric acid. (acide de mirbane), as cleansing agents. The annual cost for plant and disinfectThe chloride of lime, of a 'strength ing materials of all descriptions is £8,800 of 100° 105°, is successfully (220,000 francs). employed for the disinfecting of places The engineers of the city of Paris are tainted with urine or fæcal matter, also also charged with the sweeping of the for the cleansing of gutters carrying roads, an area of 12,916,800 square yards sewage water.

Sulphate of iron and being cleaned between 3 and 6 A. m. in sulphate of zinc are both used under the summer and between 4 and 7 in winter. same conditions. Sulphate of iron pos- The carts for removing the public and sesses the disadvantage of rusting ob- private refuse work from 6 to 8 A. M. in jects to which it is applied. Sulphate of summer and from 7 to 9 in the winter. zinc is stronger in its action, but costs a The filling of each cart is attended to little more. It produces no smell, nor by the driver aided by two shovelers, the does it leave any trace. It is much em- latter having to provide during the rest ployed in summer for washing and water- of the day supplemental sweepings ing the basements of the Halles Cen- wherever required, to rinse the gutters trales, used for fish, poultry and offal. twice a day, and to clear and disinfect At a strength of $, and mixed with 3 urinals, &c. These matters are ordiper cent. of sulphate of copper, sulphate narily finished by 4 o'clock in the afterof zinc makes a good disinfecting liquor, noon, except in unfavorable weather. which preserves its qualities a long time The engineers have all at their disposal a and is of great use in private houses. staff of: Carbolic acid is not, strictly speaking, a disinfectant; it does not act like chloride 2,200 men at from 250 to 40 per day.

950 women on putrid matter, but arrests and pre

0 20 to 0 25 per hour.

30 children (boys) at 0 20 vents fermentation, doubtless by de

hour.

per stroying the spores. It is, therefore, al In addition there are one hundred and

to

fr. c.

fr. c.

ninety mechanical sweepers, and as each removing the snow the General Omnibus machine represents the effective work of Company are bound by their concession ten men, the total scavenging staff may to furnish fifty wagons, and carts are be considered as composed of nearly five specially arranged for with the providers thousand laborers.

of sand and gravel at the beginning of The mechanical sweepers which, after winter, the contractors for maintaining numerous trials and much hesitation, the public roads being also bound to have been introduced into Paris, are the hold their carts at the disposition of the English machine, improved by M. Sohy, sectional engineers. In certain and the machine of M. Blot, the former the half-melted snow is swept into the being preferred. The mechanism of sewers, especially those carrying warm both is simple, works with regularity, water. Melting by steam has been and occupies little space; it consists of tried, when a continuous jet was introa framework upon two wheels, with a duced into a mass of banked snow, but seat for the driver. At the back is it melted very slowly at first, and the placed the sweeping apparatus, composed melting ceased after the cavity had inof an inclined circular bass broom, actu- creased to a certain size. Two descripated by gearing driven from one of the tions of snow plough are kept in store, wheels of the carriage. By means of a one for manual, the other for horse powclutch the driver can from his seat easily er; but they have never been used, as put the broom in or out of gear. The the coating of snow seldom attains suffimachine is employed in all weathers, and cient thickness, and as it is too quickly works as well on paved roads as upon ma- compressed and hardened by the traffic. cadam or asphalt. Each machine weighs As a rule the sum allowed in the budget, rather over 14 cwt., and can be drawn by about £7,000, suffices for the extra labor one horse. It sweeps about 6,578 square incurred; but occasionally severe winyards per hour. The cost of the ma- ters cause this to be greatly exceeded, chine is £40, and its annual maintenance, as in 1875–76, when the increase amountexclusive of renewals of the brush, £8. ed to £8,000. The cost of a new brush is about £2 16s. Both hose and carts are used for wa(70 francs), which will work for from tering the thoroughfares, the former for one hundred and sixty to one hundred the boulevards, the avenues, and a cerand eighty hours.

tain number of first-class streets. The The Paris 'mud no longer possesses watering plant belongs to the municipalithe manurial strength of former times, ty. Three descriptions of carts are in and in consequence the receipts derived use, two heavy wooden ones are now beby the municipality from this source ing superseded by the third, Sohy's cart, have greatly diminished. It is at pres- made of sheet iron. The carts contain ent disposed of by public terder to re- 220, 242 and 286 gallons respectively, sponsible contractors for terms of about and will water from 2,400 to 3,350 square four years. For its removal there are yards. The watering by hose is atdaily employed five hundred and twenty tended to by the ordinary street cleaners, carts, and nine hundred and eighty who can easily water 24,000 square horses. The average bulk removed per yards in thirty-five minutes, deducting day is about 2,223 cubic yards (1,700 the time necessary to connect the appacubic meters).

ratus with the mains. There are three When a fall of snow occurs, attention hundred and twenty-two water carts, is first directed to clearing the footpaths which on the average disperse 1,311,200 and crossings, so as to insure uninter- gallons of water over a surface of 7,139,rupted circulation of foot passengers. 163 square yards. A surface of 2,783-, The town scavengers sand the roads 092 square yards is watered by hose, wherever it is necessary for the carriage and this system is being greatly develtraffic. At the same time numerous aux- oped on account of its convenience and iliaries are organized to remove the snow cheapness. The annual cost of waterfrom the principal thoroughfares, in the ing is £18,000.-Annales des Ponts et order of their relative importance. For| Chaussées.

TINERARE The January and February Issues exemple lorda cemence of this lacinia.

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REPORTS OF ENGINEERING SOCIETIES.

barden by cooling. These, instead of gaining

their strength slowly, like those of class two, HE AMERICAN SOCIETY OF CIVIL ENGI- / become hard at once. Shellac is a good

Chipa of Transactions, contain:

put together with melted shellac is extremely Paper No. 214. “The Strongest of the strong. Bronzes; a Newly Discovered Alloy of Max A fourth class of cements may be repreimum Strengtb,” by R. H. Thurston.

sented by plaster of Paris. This is the type No. 215. * Renewal of Foundation and of an extensive class, including the whole Transfer of a Lighthouse in Pascagoula Har- lipe of mortars and hydraulic cements on bor," by J. W. Putnam.

which depend our great engineering works, No. 216. “The Sewerage of Memphis,” by and even the houses in which we live. It F. S. Odell.

forms chemical compound combination The papers are fully illustrated and the dis- with water first, and then more slowly cussions of the latter paper are of unusual in- hardens by drying a part of the water evapterest.

orating

In order to use a cement successfully we OLYTECHNIC ASSOCIATION OF THE AMERI- must know to what class it belongs and treat 17th March, the paper for the evening was by put it on. In no case should it be used in a Prof. Plympton upon the aneroid barometer. large quantity. The less the better is a good This instrument has been greatly misunder rule to follow. stood, and has been much abused because peo In moriar we mingle sand, which makes the ple, in buying it, have often supposed that actual thickness of the lime between the stony they would be able, by inspection, to read off surfaces in all cases very slight, however much the elevations at which tbey made their obser. mortar we may employ. Iu the use of glue vations, in the same way that they would note this is not practiced or necessary. The the temperature upon a thermometer. Like joints made by carpenters are good examthe mercurial instrument, it is a measure of ples of the minute quantity of a cement the pressure of the atmosphere at any given which is necessary. Place a well-made glued time.

joint on the edge, and it is almost impossiIn torrid zones, where the variations of ble to find the lines of glue. Its position is pressure are sudden, especially those just pre- mainly discovered by the direction of the grain ceding severe storms of wind, &c., the mercu- of the wood. rial instrument does not indicate with sufficient Intimate contact between the cement and rapidity. It is an accurate balance, though the edges is necessary. This is not easy, on rather slow to swing. Its numerous disadvant- account of the layer of air which adheres to ages as a portable instrument were mentioned, all bodies. This layer of air is what causes and its construction illustrated experimentally. needles to float when carefully placed upon The construction of the aneroid was then de- the surface of water. When an object is scribed, and drawings were made upon the warmed the film of air is easily moved, the board. Almost a dozen different styles and hot peedle sinks, and to the hot body the cesizes of instruments were then exhibited, from ment will adhere easily. It is faulty for this the 5-inch instrument to the delicate affair no reason, that in gluing it is peedful to have the larger than a watch.

work warmed. The rubbing of the surfaces The paper of March 24th was upon glass and together gets rid of the air, and then not only cements, by Dr. John Pbin, of the American with glue, but with all cements, the surfaces Journal of Microscopy.

must be pressed closely together, Cements are to be divided into four classes, Common glue has most enormous strength according as they dry, congeal by oxydation, and adhesive powers if it is good. But to be harden by cooling, or set " by other chemical good it must not have been injured in the changes. First are those which harden by making by decomposition, to which the mateevaporation. Under this head may be classed rial and the glue itself are peculiarly subject. paste, mucilage and their varieties. Glues to Here the lecturer detailed at some length the a certain extent dry.

process of glue making, and said that if glue The second class includes the oils. These' was not pleasant to both taste and smell it are said to dry, but it is not by evaporation. would not be strong. If not offensive, it could They lose nothing, but absorb oxygen from be trusted to hold wood more strongly than its the air. The cement weighs more after hard- own fibers. ening than when first applied. Cements which ! The strongest known glue is that made from congeal by oxydization cannot be treated in the the skins and sounds of fishes, and the same way as those of the first class. They re strongest of this class is made in Lapland quire a larger time to handle. The hardening from the skin of a perch. The Laplanders use goes on from the outside inward. For exam- it in making their bows, which are both strong ple, mend a piece of porcelain with one of and durable. In making it their cold climate ihese cements. Test it in a few days, and al. is greatly in their favor; here a fish skin will though the outside will be hard the inside will begin to undergo decomposition before it can not appear to have dried in tbe least, and will be dried. have no tenacity. Leave it for six months, and In making it the skins are put into a bladit will be very strong.

der, which answers for a water bath, and heated Thirdly, we have those cements which in water until a sort of glue results. Tbis

Vol. XXIV.-No. 5–29.

glue is, as may be imagined, very elastic. himself had used was that known as “D. H. Isinglass is a very strong glue, made from K.," and he had had no difficulty in making it skins, sounds, &c., of fishes; it is very adhere to glass—a point which caused some liable to be spoiled in making by overheat- surprise. ing. The pastes are all made from starch in some

PHILADELPHIA, of its forms. Gluten is also used for a paste,

ENGAPREL 2, 1897.5DO. I. but starch is the best. All additions of resin, scribed an attempt to extinguish the Kebley &c., commonly recommended, are a damage to Run Colliery fire at Shenandoah City, by car. paste.

bonic acid gas and nitrogen. The gas was gen. Dextrine, or “British gum,” is of immense erated in an open brick furnace with reversed value in the arts as a cement. It is derived draught, and forced into the mine through from starch by roasting or by the action of four 3-inch pipes, by injectors supplied with nitric acid. It was discovered by accidental steam at 60 Îbs. pressure. Each pipe was supoverheating of starch, and its process of man- posed to supply 1,500 cubic feet per minute, or ufacture was for a long time kept secret. Its a total of 6,000 cubic feet per minute. The chief use for a long time was in the cotton attempt was entirely unsuccessful, and Dr. manufacture. It is the standard gum for Chance attributes its failure principally to the postage stamps, though it is said that gum- impossibility of making the mine airtight, but arabic and cheaper substitutes are used in this also considers that the gas was delivered at country

too high a temperature, and that it was possiNo cement can be fire-proof which contains bly mixed with carbonic oxide. The method organic matter, since this is decomposed at a seems to be worthy of further trial at mines temperature about that of melting lead, or, that can be made thoroughly airtight. say, 600° F. Cements containing oils will not Mr. P. H. Baermann described briefly the be fire proof.

construction of the Cooperstown, N. Y., Water Silicate of soda, mixed with asbestos, is the Works, and particularly the method of laying nearest to a fire-proof cement. It will stand the supply pipe extending from the pump a low, red heat. It is decomposed at a bright house up the Susquehanna River into Otsego red.

Lake, a distance of 4,500 feet. The pipe was Water proof glues are made in two ways. laid from a staging carried on 120 barrels, and Glue and linseed oil are recommended, bui I lowered in 108 feet sections. Up to 9 feet in have had better success with the mixture. The depth the joints were made with dry pine chromates may be used with glue. These, wedges, and above this with lead. The end of when exposed to the light, render the com- the pipe is provided with a copper strainer, pound insoluble.

which is in 38 feet of water and 10 feet above Aquarium cement is the best water-proof ce- the bottom. ment I know. The formula is :

A paper was also read by Dr. Chance on Litharge.. 3 | Rosin.

“Wear in Wire Ropes,” showing that the

1 White sand. 3 Boiled linseed oil..

cause of rapid wear is often due to the use of

drums, sheaves and pulleys of insufficient size, Plaster of Paris.... 3

and that a great saving might be effected by The solids are to be taken by measure in increasing their diameters; especially that of powder and mixed. As it sets rapidly, the set the small deflection and knuckle pulleys and must not be added until it is wanted for use. sheaves. The actual wear averages 0.138 cents It is better for being put into a mortar and in slopes, and 0.053 cents in shafts, per ton, for pounded. It hardens in three days. It will each hundred feet of lift. hold glass firmly, and with it glass tanks may be made without frames, if the angles are well filled with cement. It is a kind of mastic,

ENGINEERING NOTES and could be used on brick. stands almost by itself. Where it can be put

DVICES from Vienna state that the prepars A

atory operations having been finished, on hot is admirable. It is composed of India the work of boring the great tunnel through rubber and shellac, dissolved in naphtha. Some the Arlberg bas now actually commenced. kinds are hard, some almost liquid. I have This tunnel will be one of the longest in the seen this glue adhere to glass so firmly as world, though not so long as that of St. Gothto tear the glass when plates were separated. ard. So far the operations on the eastern side

In the discussion which followed, Dr. Parma of the Arlberg have progressed very favorably. lee gave some interesting experiences in the The rock there found is a micaceous slate, manufacture of marine glue. · He said its through which the contractors find it possible melting point was about 230°, and in making to advance at the rate of from three to four it was injured if the heat was carried above meters a day. On the western side, on the this point. In applying it care should be taken other hand, the advance of the tunnel is renot to go above this heat, as the melting point tarded, and the operations frequently disturbed would be raised and the strength diminished by the repeated inrush of large quantities of waIn applying it the soldering iron may be used, ter. The contractors were warned before combut its neat must be regulated.

mencing the work that this was only to be ex. In answer to Dr. Parmalee, Dr. Phin said pected. The geologist further advised that the that Jeffries, the inventor, put three kinds of tunnel should be carried through a lower stra. marine glue in the market; that the kind he tum of rocks, which are of denser material

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