1844,] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



311 



aliout 1500 square yards of levtl pavement cleansed in less than 20 niinulcs 

 by water acting under a pressure of 80 feet. 



Watering Gardens. 



In respect to the watering of gardens, it would appear that one man with a 

 jet of the force to rise 50 feet perpendicular height would with that one jet, 

 at an angle of 45 degrees, command an area of about 2000 square yards. 

 From your information, that about 40 jets would command a length of a mile 

 of road, and that one man might water that mile twice a day, may it not be 

 inferred that by a proper distribution of pipes and arrangement of cocks one 

 man might water 20 acresofgarden ground inaday? Yes; foralthough2miles 

 of such a road contains only 10 acres, the range commanded by an equal num- 

 ber of jets would in a garden command twice that area, and the interruptions 

 would be much fetter than in a public road.— It is stated lobea heavy wetting 

 shower when the e.tcess fills gutters, and, running away, covers the ground 

 to the depth of a quarter of an inch. How many tons of water would fall in 

 such a shower on an acm ? A fall of rain sufficient to cover tlie earth to a 

 depth of -nrth of an inch will, under ordinary circumstances, fully saturate 

 the dust of a public thoroughfare: this quantity is equal to 750 gallons, or 

 about 3i tons, or 2 loads of water per acre. — In what time would such a ijuan- 

 tity be delivered from a hose by a jet under the moderate pressure of 50 feet? 

 The velocity, and consequently the time, will in some degree depend upon the 

 arrangement ot the apparatus : a coniracted ^et, issuing under a pressure of 

 50 feet, at a |ths aperture, will deliver 750 gallons in 14 or 15 minutes; a 

 judiciously formed nozzle will deliver the same quantity in 10 minutes. — The 

 rate of expense of laying down a set of water pipes per acre would l:e from 

 1.5/. to 30/. according to circumstances, and at the cost of supply at Notting- 

 ham of Sd. per 1000 gallons a fall of water equivalent to a shower would be 

 given at Ifd. per shower per acre. 



It is slated by Mr. Braidwood that, in London, 26 men working an engine 

 of two 7-inch barrels will throw a rgth of an inch jet 50 feet high ; and the 

 following is an account of some experiments made at the works of the South- 

 wark Water Company, to ascertain the capacity of the existing works to 

 aflbrd several jets for street cleansing or for extinguishijig fires. 



Experiments on Jets or Water. 

 " Remit of Experiments made on the Zlst January, \6H, to ascertain the 



Height that a Jet of Water trill rise from the Mains and Services belony- 



ing to the Southwark Water Comjiany, under a Fixed Pressure of 120 



Feet. 



The first trial was made in Union-street, between Iligh-strcet and Gravel- 

 lane, Ijorough, over an extent of 800 yards of /.inch main, and through the 

 fire-brigade stand-pipes, hose, and jets. 



This 7-inch main is connected to the 9-inch main in the High-street, 

 Borough, which, after a run of 500 yards, is joined to 200 yards of 12-inch 

 main, and then continued by 550 yards of 15-iuch main to the great main 

 leading from the Company's works at Battersea, making a total distance ot 

 5500 yards from the place where the experiment is made. 

 One 24-inch stand pipe, with 40 feet of hose, and f-inch jet, rose 50 feet. 

 Two 2-\ „ „ 40 „ i „ 45 „ 



Three 2i „ „ 40 „ i „ 40 „ 



Four 2i „ „ 40 „ i „ 35 „ 



Five 2i „ „ 40 „ i „ 30 „ 



Six 2i „ „ 40 „ i „ 27 „ 



Then all the fire-plugs on the main were closed except the first and one 2.J. 

 inch stand-pipe, with IGO feet of hose, and a J-inch jet rose 40 feet. 



The quantity of water delivered from the same main through one stand- 

 pipe and dift'erent lengths of hose was as follows, viz. : — 

 One 24-in. stand pipe, 40 feet of hose, |--in. jet, delivered 96 gals, in 59 see. 

 One 2^ „ 80 „ | „ 112 „ 65 „ 



One 2i „ 160 „ J „ 116 „ 70 „ 



One 2^ „ 40 „ 2J „ 118 „ 27 „ 



The second trial in Tooley-street oif a 9inch main, 1400 jards in length, 

 connected to 1000 yards of 15-inch, and 6650 yards from the works. 

 One 2i-inch stand pipe, 40 feet of hose, |-inch jet, rose 60 feet. 

 Two 2J ,, 40 ,, f-inch, difference not perceptible. 



Four 2i „ 40 „ |.inch jet, rose 45 feet. 



Six 2J „ 40 „ I „ 40 „ 



Quantity delivered from the same main through — 



One 2J-inch stand pipe, 40 feet of hose, J-inch jet, 114 gals, in 64 sec. 



Four 24 „ 40 „ J „ 115 „ 75 „ 



Six 2| „ 40 „ J „ 112 „ 78 „ 



Four-inch service in Tooley-street, 200 yards long, supplied through 200 

 yards of 5-inch pipe, from flinch main one 24-inch stand pipe, fixed on the 

 4-inch service near the 5-inch pipe, with 40 feet of hose |-inch jet, rose 40 

 feet; two 2j-inch stand pipe |-iiich jet, rose 31 feet. 



One 2.J-inch stand pipe fixed at end of service. 

 200 yards from 5-incli pipe, 40 feet of hose, |-inch jet, rose 34 feet. 

 Two 2J-inch stand pipe, 40 ,, | „ 23 „ 



Quantity delivered from the plug near the 5-incli main through — 



One 2 J-inch stand pipe, 40 feet of liose, |-iuch jet, 112 gals, in 82 sec. 



Two 24 „ 40 „ I „ 117 „ 103 „ 



Quantity from end plug of service 200 yards from the 5-inch main — 

 One 2^-inch stand pipe, 40 feet of hose, finch jet, 112 gals, in 90 sec- 

 Two2| „ 40 „ I „ 114 „ 118 „ " 



In confirmation of these results it is staled in answer to some inquiries 

 made at Philadelphia, that " the water will rise from a hose attached to a 

 fire-jilug in the street at the extreme point of delivery, during the night to 

 the height of about 45 or 50 feet. During the day when the consumption of 

 water is very great, it w ill not rise more than 20 to 30 feet. Do these results 

 correspond with your experience and observations? — Yes, they do. But it 

 may be well to state that the great diminution of velocity, and consequently 

 of elevation, observable in the least favourable experiment of each set, is to 

 be chiefly attributed to the great aggregate area of the jets in proportion to 

 the area of the stand-pipe and hose. 



Although the height to which water will rise from jets is in general, in 

 consequence of the resistance of the atmosphere, half the height due to the 

 pressure, will it not. in a hose or in a pipe, rise to the lull level, so that it 

 may be poured out to extinguish fires, or used for any purpose from tliK full 

 height? — When the water is not in motion, it will lise to the level of the 

 reservoir. M'hen it is in motion, there will be friction in the main pipes, by 

 which the height will be in some degree diminished. When the main pipes 

 are of considerable size, compared with the area of the jet, this friction will 

 be insignificant. The higher water is carried in a pipe, or the higher the 

 nozzle of a hose pipe is carried, the more the resistance of the atmosphere is 

 avoided. If a jet acting under a pressure of 100 feet, attained an elevation of 

 50 feet when discharged from the level of the pavement, then if the hose pipe 

 were elevated to the height of 50 feet, a jet would still be given of probably 

 20 or 25 feet high. By this means the water would attain an elevation of 70 

 or 75 feet high, in place of 50 ; hence the advantage of carrying a hose-pipe 

 up-stairs, or up a ladder, or as nearly as possib'e to the height of the story 

 where the fire occurs. Another advantage gained by carrying up the hose 

 pipe is a better direction of the jet, and^more certain application of the water 

 than can be had from the ground. 



Expense of Raising Water by Steam Power, by Mr. Farby. 



To give a correct iilea of the performance of the most economical steam- 

 engines yet constructed, Mr. Farey has made the following computations : — 



Taylor's engine, at United Mines, which has made the highest performance 

 of any yet constructed, has on an average of all the variations of its i)erl'orm- 

 ance, during the 12 months of the year 1841 raised 921 millions pounds weiglit 

 of water, one foot high, by each bushel of coal w hich has been consumed by 

 it ; and in 1842 the average was 90| millions. 



An average of the two years would he 9511 millions. A bushel of the coal 

 actually used is considered on an average to weigh 94 pounds, and if Taylor's 

 engine bo reckoned to raise only 94 mMlions pounds one foot high, by the 

 consumption of each bushel of 94 pounds, then one pound of coal will raise 

 one million pounds of ivater one foot high. 



As a million pounds is not a very conceivable quantity, it may be consi- 

 dered as 16,000 cubic feet of water (which reckoning each cubic foot to weigh 

 02; pounds, would be a million pounds weight) raised one foot high. Or if 

 the height be reckoned at 10 feet, instead of one foot, then it would be IfiOO 

 cubic feet of water raised 10 feet high, by the combustion of one pound of 

 coal. 



To render this more clear, suppose an apartment 20 feet square on the floor, 

 between the walls, to be filled 4 feet deep with water, like a large bath, it 

 would contain the 1600 cubic feet of water. And supposing another upper 

 apartment of the same size over the former, the height from the lower floor 

 to the upper floor being 10 feet, then with the corsumption of one pound of 

 coal Taylor's engine would exert a sufiicient power to raise all thevvaterfrom 

 the lower apartment into the upper uno, in addition to overcoming the frictim 

 of all the moving parts of the engine and of its pcunp work. 



A robust labouring man, possessing such strength and capability of endur- 

 ing exertion, as is an average of that class of men in Britain, would bo inces- 

 santly employed during 4 hours 26j minutes in performing the above work , 

 such a man could work at that rate during 10 hours in a day, and six 

 days in a week. Taylor's engine would perform the day's work of the man 

 with a consumption of only 21 pounds of coal. 



A good draught horse would be -155 minutes in performing the above work 

 and could continue to work ,at that rate during eight hours in a day, for six 

 days in a week. Taylor's engine would perforin the day's work of the hors e 

 with the consumption of lOJ pouncU of coal. 



What is called ahorse power in steam engines, as fixed by Mr. Watt, viz. 

 33,000 pounds force acting through a space of one foot per minute, is half as 

 much more as the average of what a good draught horse can do, so as to con- 

 tinue working during eight hours per day, and for six days per week. 

 ^Taylor's engine, (or any other,) when raising 94 millions [ler bushel, con- 

 sumes only 1'98 pounds ol cual per hour fur each horse power which is exerted 

 by it in raising the water, independently of overcoming its own friction, and 



