ccxii GENERAL SUMMARY OF SCIENTIFIC AND 



run up beyond one half their capacity, and have since the date of 

 their going into operation been supplying, on an average, 150,000 

 cubic feet of 20-candle gas daily (a quantity quite sufficient to meet 

 the local requirement), and employ the services of but seven men 

 three on the night shift, and four during the day. The cost of 

 20-candle gas delivered into the holder, inclusive of labor and inter- 

 est on the investment, is admitted by the managers to be from 35 to 

 40 i^er cent, less than that of the coal gas of 16-candle power which 

 the old works had been supplying ; and this estimate will doubtless 

 be still more favorable when the works are running up to their full 

 capacity, and wiien the price of oil, which has of late been excep- 

 tionally high, returns to its normal market value. The capacity of 

 the Manayunk plant is placed at 350,000 cubic feet daily, and the 

 total production from August 4th to December 31st, 1876, has been 

 20,000,000 cubic feet. The progress that is being made in this di- 

 rection will be best appreciated by the statement that during the 

 past year the Lowe process has also been introduced at the Falls of 

 Schuylkill and Stroudsburg, Pennsylvania, and at Clyde and Fort 

 Plain, New York. At Kingston, Canada, Lowe works are at present 

 in course of erection, and contracts have been effected for the build- 

 ing of works at the cities of Lancaster and Harrisburg, Pennsylva- 

 nia ; Trenton, New Jersey ; Baltimore, Maryland ; and Indianapolis, 

 Indiana. The important bearing of this " water gas " system upon 

 metallurgy and the domestic arts will apjDear in its proper place. 



The introduction of the electric light into general use is likewise 

 worth noticing. The experiment of ai3plying it on shipboard ap- 

 pears to have been tried with satisfaction on the General Transat- 

 lantic Steamship Company's steamship Ameriqye, which has for some 

 time been provided with one of Gramme's magneto-electric machines. 

 The electrical signal light of the Amerique, when placed at the 

 height of thirty-three feet above the water, is estimated to be visible 

 for a distance of ten miles to an observer stationed twenty feet above 

 the water. The advantages of the electric light are not confined, 

 however, to lessening the risk of collision, but its powerful illuminat- 

 ing quality has been found extremely useful in loading and unload- 

 ing, and in working the ship, and in guiding her in and out of port 

 at night. By means of a cone of sheet-iron placed over the light, 

 with the base of the cone uppermost, all the details of the ship's 

 equipment are rendered visible for a considerable distance aside 

 from the signal light. It is afliirmed that the apparatus is inexpen- 

 sive in operation, easily managed, and not liable to get out of order. 

 The system of electric lighting has also, according to account, been 

 successfully introduced at the def)ot of the Northern Railway in 

 Paris, in several French industrial works, and in several Belgian 

 coal-mines. 



The use of chloride of calcium for watering the streets of large 



