FLOW OF WATER THROUGH PIPES.
DOWNING gives the following formula for the flow of water in a smooth pipe of small and uniform diameter, when the pipe is filled with the flowing water: _
V= 50 h/lxd
in which v = the velocity in feet per second.
h — head, in feet, equal approximately to 2 1/4 times the pressure in pounds per square inch.
I = length of pipe, in feet. d — diameter of pipe, in feet.
Therefore, the quantity of water discharged in cubic feet per second,
Q = .7854 d2x50 hd/l when the pipe runs under full pressure; or Q= 39.27h / lxd5
The number of cubic feet per minute will, therefore, equal
and if the diameter of pipe is expressed in inches and termed D, the number of cubic feet discharged per minute will equal
4.72 D5h / l
The number of gallons (U. S. Standard) discharged per minute, the diameter of pipe being expressed in inches, and the pipe running full, will equal
35.3 D5h / l
The discharge per hour under the last-named conditions will equal, in U. S. gallons,
2118 D5h / l
PROTECTION OF BUILDINGS FROM LIGHTNING.
THE French Minister of Public Instruction recently submitted to the Academie des Sciences an important question concerning the fitting of lightning conductors for public schools and other large buildings. It appears that a departmental commission represented to the minister that it was necessary in a particular case to connect all the iron stairs and other internal metal work of a school building with the lightning conductors, so as to prevent the danger of lightning leaving the outside conductors and striking through walls or roofs at the insulated metal inside. The minister logically concluded that if this was done for one building, it should be done for all similarly circumstanced ; and as this action would involve the expenditure of a considerable sum, he asked the opinion of the academy upon the point.
The committee to whom the question was referred have reported to the effect that it is indispensable for the perfect protection of buildings from lightning that the conductors should be well connected with all important metallic masses inside. The case applies not only to iron in roofs, partitions, or staircases, but also to gas and water pipes, heating apparatus and similar metallic fittings. It is laid down also that where there are many lightning conductors attached to a building, the nearest of them should be placed in connection with the metallic masses in question. It is understood on the part of the committee that the lightning conductors themselves are always properly “grounded,” by being put in perfect connection with the earth by means of a well which is never dry.
This general method of increasing the factor of safety in buildings, in case of lightning stroke, has been advocated by scientists for the past twenty-five years. It has been repeatedly shown how faulty, if not useless, is the ordinary lightning rod system, where the lower end of the rod is simply stuck a foot or two into the dry ground ; and we have urged, first, that the rod must have a thorough and extensive conducting surface in contact with the earth ; second, that all metallic fittings both within and without the building should be connected with the rods, or with special rods leading to the ground terminals. Where there are underground metallic pipes, such as water, gas, or drains, the rods should be connected with them. If there are no such metallic pipes or masses, then long trenches leading away from the building should be dug, deep enough to reach moist ground, pulverized coal should be placed in the bottom of th; trenches, and the lower end of the rod extended for a considerable distance in the trench in contact with the coal, which is itself a conductor.
THE LONDON FIRE DEPARTMENT IN 1886.
THE report of Captain E. M. Shaw, chief of the fire department of London, England, for the year 1886, reads as follows :
The number of calls for fires, or supposed fires, received during the year has been 2853. Of these 540 were false alarms, 164 proved to be only chimney alarms, and 2149 were calls for fires, of which 151 resulted in serious damage and 1998 in slight damage.
These figures only refer to the regular calls for fires, or supposed fires, involving the turning out of firemen, fire engines, fire escape, horses and coachmen. They do not include trifling damages by fires, which were not sufficiently important to require the attendance of firemen ; neither do they include the ordinary calls for chimneys on fire, which are sepaiately accounted for further on.
The fires of 1886, compared with those of 1885, show a decrease of 121 ; but, compared with the average of the past ten years, an increase of 246.
The following table gives the result both in actual numbers and percentages (this table shows 1338 in 1866, with an average of twenty-five per cent serious fires, gradually increasing up to 2149 in 1886, with an average of seven per cent serious).
The number of fires in the metropolis in which life has been seriously endangered during the year 1886, has been 136, and the number of these in which life has been lost has been 41.
The number of persons seriously endangered by fire has been 175, of whom 126 were saved, and 49 lost their lives. Of the 49 lost, 29 were taken out alive, but died afterwards in hospitals or elsewhere, and 20 were suffocated or burned to death.
The following is a list of the firemen whom I have commended for special merit in saving life from fire during the year: Henry E. Hill, Wm. E. Tozer, James Thomas, G. A. Bettinson, Sydney Sharp, H. T. Dawson, William Gordon.
Details of the 136 cases in which lile has been endangered will be found in another part of this report.
The number of calls for chimneys has been 1658. Of these 565 proved to be false alarms, and 1093 were for chimneys on fire ; in these cases there was no attendance of engines, but only of firemen with hand pumps.
The number of journeys made by the fire engines of the 55 land stations has been 32,832, and the total distance run has been 61.768 miles.
The quantity of water used for extinguishing fires in the metropolis during the year has been a little more than 10,000,000 gallons, or about 45,000 tons. Of this quantity nearly 1400 tons, or about a third of the whole, was taken from the river, canals and docks, and the remainder from the street pipes.
During the year there have been 9 cases of short supply of water, 10 of late attendance of turncocks, and to of no attendance, making altogether 29 cases in which the water arrangements were unsatisfactory.
This is a considerable improvement on the previous year, in which there were 39 such cases, and I have great pleasure in recognizing the successful exertions of the water companies and their officials in the matter.
I have also, as usual, to express our great obligations to the Metropolitan and city police, whose cordial and energetic co-operation has never failed us at any time.
The strength of the brigade is as follows : 55 land fire engine stations, 4 floating or river stations, 26 hose cart stations, r27 fire escape stations, 4 steam fire engines on barges, 45 land steam fire engines, 77 six-inch manual fire engines, 37 under six-inch manual fire engines, 28 miles of hose, 63 hose carts, 3 self-propelling fire floats, 4 steam tugs, 7 barges, 146 fire escapes, 9 long fire ladders, 9 ladder vans, 2 ladder trucks, 1 trolley for ladders, 1 trolley for engines, 12 hose and coal vans, it wagons for street duties, 4 street stations for street duties, 105 watch boxes, 589 firemen, including chief officer, second officer, superintendents and all ranks, 16 pilots, 66 coachmen, 131 horses, 28 telegraphs between fire stations, 39 telepones between fire stations, 54 alarm circuits round fire stations, with 347 call points, 3 telegraphs to police stations, 18 telephones to police stations, 14 telegraphs to public and other buildings, 20 telephones to public and other buildings, 15 direct fire alarms to public and other buildings.
The’substitution of telephones for telegraphs, which was commenced some years ago, still continues, and though for financial and olher reasons carried out only gradually, has proved a great advantage. We are now proceeding more rapidly, and I anticipate that before the end of 1887 the change will be completed throughout the whole of our system.
The number of firemen employed on the several watches kept up throughout the metropolis is at present 113 by day and 244 by night, making a total of 357 in evety24 hours ; the remaining men ate available for general work at fires.
Our list of wounds and olher injuries for 18S6 is, as usual, very heavy ; but the nature of the work, and the way in which it is always carried out, involve a certainty of numerous accidents.
There have been during the year 254 cases of ordinary illness and 90 injuries, making a total of 344 cases, of which many were very serious and two resulted in death.
A reference to the figures in this report will show that the total number of calls, including those for actual fires, supposed fires, chimney fires and supposed chimney fires, has been 4511, more than 12 a day, all of which have been attended by firemen with suitable appliances.
In addition to the tires we’have kept 130,305 watches of 12 houts each, have maintained all the machinery of the brigade in working order, written several thousand reports and letters, and carried on a variety of other work.
This represents a severe amount of labor for so small a force ; but all ranks have worked cheerfully and well, and I trust that the result may* be considered satisfactory.
From the tables accompanying the report we find that no less than 297 fires occurred at lodgings ; 61 of these cases were “ spirit-lamp upset,” and 25 “ spirit-lamp exploding.”
Five hundred and thirty-five fires occurred in private houses, only 4 of which are described as serious ; 34 from ” spirit-lamp exploding and 44 “ spirit-lamp upset.” In the list of causes of fires we find that ” light thrown down ” heads the list with 155, followed closely by “ spirit-lamp upset’’with 130; “spark from fire,” 123 ; “ candle,” 119; “spirit-lamp exploding,” 67 ; while those cases which are described as “ unknown ” run up to 700, or about one-third of the total.
The hour in the day in which the largest number of calls have been received is from 9 to 10 P. m.—2×8 ; while from 6 to 7 A. M. only 37 are registered.
During the week ending July 8, 91 calls were received, followed by 83 calls for the week ending December 23.
The lowest number of calls in a week was for the week ending Novi mber 18, being 34. In the month of July there were 282 calls, and in December 297. the lowest month’s record being January, with 188.
One paragraph in the report is worthy of attention, as to the gtcat utility of what is known as the London Brigade hand-pump. Over 1000 fires were put out by means of this appliance without calling in the aid of engines or street mains.
STANDARD SPECIFICATIONS FOR CAST IRON PIPE.
AT the last meeting of the American Water-works Association, George W. Pearsons presented the following interesting notes, as his contribution to the discussion on the subject of Standard Specifications for Cast-iron Pipe :
Uneven Castings.—In past discussions the fact of pipe being sometimes thinner on one side than on the other, has been passed over as a rare, and probably not very serious fault. My experience in laying some 130 miles of cast-iron pipe and its test by direct pressure, leads me to consider it one of the most common and serious faults we have to contend with a large majority of the broken pipes 1 have seen showing it. I speak of pipe broken in the ground by pressures.
Quite frequently l have found such pipe broken with an irregular, an. gular fracture, always on the thin side. The fracture, instead of being radial, being diagonal to the surface and resembling a rough tear. I have never seen such a fracture made by breaking a pipe in any other manner, and think it must be due to unequal contraction in cooling, caused by the unequal thickness.
Such a pipe is dangerous whether it has passed the test or not all such pipe which I have seen broken have been tested to 300 pounds, according to the statement of the manufacturers—and, notwithstanding they showed no fault on careful inspection before laying, have generally given way before the pressure reached roo in the ground.
Pipe can be tested for unequal thickness by being rolled slowly over level skids by a single person—any pipe which shows a disposition to get away should be allowed to—and assisted to do it. The best place to do this is in the the pipe factory before the pipe has gone into the tar bath, and I think if the importance of this was realized by the makers, it would be done.
I know as regards water test that all I have seen has been apparently done with proper care ; but do we, or even the manufacturers, know that their workmen are always faithful in this if they are not well watched ?
Pipe Weight.—My experience fully justifies the use of as light pipe as indicated by the discussion.
Lead Room.—How can a reasonable uniformity of lead room be maintained ? I have had a gang of thirty men up all night, chipping the spigot end of two specials to get them into the bowls they must go into, all standard weight pipe from the same factory, and from the same factory have laid pipe in which the lead room was from five-e ghths of an inch to over one inch.
Remedy.—Call for standard outside sizes of pipes, and require all manufacturers to conform to these sizes, leaving the inner diameter to be governed by the thickness of the pipe. Most of you lay pipes from different factories, and I presume like myself, have suffered from the difference of sizes.
Yarn and Lead.—The yarn should fill to the lead score ; the bead on the pipe takes with some irregularity in alignment perhaps one inch ; yarn, one inch ; lead, one and one-half inches ; three and one-half inches, say three inches in small pipe, and four inches large is deep enough for the bowl.
How to Get Good Pipe.—Buy it by the lineal foot instead of by the ton ; specify, if you desire the minimum thickness to be used, and the water test required ; then the manufacturers will take pains to keep out ovt r weight, and will be enabled to make skill in manufacture a paying item in their wotks. As it is now, the superiority of one maker over another in this particular has no market value ; buy specials by the piece.
THE DIMENSIONS OF THE BARTHOLDI STATUE.
AT the request of a correspondent, who must surely have spent last summer and fall in the backwoods, beyond reach of the daily press, we give below the full dimensions of Bartholdi’s Statue of Liberty, in New York harbor:
OF THE STATUE.
Forty persons can stand comfortably in the head, and the torch will hold twelve people.
The number of steps in the statue, from the pedestal to the head, is 154, and the ladder leading up through the extended right arm to the torch has 54 rounds.
SPARROWS AS INCENDIARIES.
A CORRESPONDENT of The Scientific American, writing from Poltsville, Pa., tells the following curious tale, which reveals a hitherto unsuspected cause of fire :
There is a bar iron mill situated in a neighboring town, four miles from here, that has been on fire three or four times, in which the English spartow might be called the incendiary. These spartows pick up old pieces of cotton waste, which they build in their nests, among the timbers of the roof of the mill, and, in every case of the fires above mentioned, these nests were the cause, either from spontaneous combustion or from sparks from the hot iron striking and lodging in the nest.
CHIEF ENGINEER HENNICK ON CHEMICAL ENGINES.
A STRIKING tribute to the value of chemical engines is paid by Chief Engineer Hennick of the Baltimore Fire Department in his recent annual report. He says:
I respectfully ask your attention to the urgent necessity of purchasing chemical engines, and placing them in service as an adjunct to each hook and ladder company. I would recommend single-tank engines, of 100 gallons capacity, as they require only one horse and the service of two men to operate them. The experience of chemical engines for extinguishing fires has proved successful wherever they have been tried. In other cities they are used ; and where stores are stocked with goods that are most likely to be damaged by water they are invaluable. During the past year a number of fires have occurred in the mercantile district, where these engines could have been worked to great advantage, and a considerable amount of property saved. The hose, being small and light, can be carried quickly to the top stories of the highest buildings, and the fire extinguished, where it would take considerable time to carry up the heavy hose, and the loss of time allows the fire to gain considerable headway ; and when large fires occur, we could, in addition to the steam engines, have the chemicals to protect adjacent property, which would be endangered by sparks, which sometimes communicate fire to buildings squares away ; and in such cases the chemical engines, carrying their own material for extinguishing fires, could be made available.
STANDARDS FOR HOSE COUPLINGS.
THE American Machinist, having inquiries as to the standard for hose couplings, recently wrote to the Button Fire Engine Company of Waterford, N. Y„ about the matter. To this letter the company replied : “ There is no universal standard for hose couplings, but there is no end of private standards. The ones most in use are known as the New York, Chicago, Boston, Philadelphia, National, etc. But when we furnish work for departments we get a sample of the couplings in use, or if they have none we give them one to suit our convenience. If possible we make it like those in the cities near them. Some years ago the National Association of Fire Engineers adopted a standard which they described carefully in their printed reports. It has never been adopted by departments generally, and never can be. No two builders who followed the directions made exactly the same thread, so where two towns are using the National standard the chances are they would be found so different that they would not connect. It would be very nice if all could be alike, but we do not see any way by which it could be brought about.”