674 



SCIENCE 



[N. S. Vol. XXVIII. No. 724 



hall there are three laboratories adjoining 

 one another for water, bacteriological and 

 gas analysis. In the gas analysis room we 

 have found it satisfactory to build the 

 floor of asbestolith composition, which does 

 not crack, so arranged that the baseboard 

 and floor are all one piece and slope 

 slightly to a central cup for the collection 

 of mercury which may fall upon the floor. 

 In the gas analysis room we have also a 

 tin-lined tank holding 100 liters of dis- 

 tilled water, so that gas measurements are 

 made with distilled water of the same tem- 

 perature as the room. 



The advanced analytical laboratory is 

 provided with drying ovens, like those in 

 the Massachusetts Institute of Technology, 

 steam baths, such as one sees in the Har- 

 vard laboratory, closed and open hoods. 

 These are constructed of glazed brick, set 

 in cement and pointed up with plaster of 

 Paris. The steam baths are constructed 

 of alberene covered with a series of porce- 

 lain rings and are placed opposite plugged 

 vents. Constant water-level contrivances 

 are connected. The water is heated by 

 means of high-pressure steam. In the 

 basement we have a small room adjoining 

 the assay room, which contains grinding 

 machinery, pulverizing and bullion mills, 

 and also types of furnaces, such as wind, 

 down-draft gas, muffle and annealing 

 furnaces. 



Except in the case of the laboratories for 

 general chemistry, there is a private 

 laboratory for an instructor adjoining each 

 laboratory in which the students are sup- 

 posed to pursue a particular course. 



In the basement we have a machinery 

 room, containing two filtering plants, a 

 ■drum for heating water, compressed-air 

 engines, and water and vacuum pumps. 

 In the line of the vacuum piping there is 

 inserted, just before it reaches the pump, 

 a scrubbing apparatus built of cast iron, 

 lined with porcelain. Three of the-e 



drums are arranged so that the gases which 

 pass into the vacuum pump are passed 

 through a tower of pumice saturated with 

 concentrated sulphuric acid ; another tower 

 containing solid caustic and the third one 

 is placed in front as a safety reservoir. 

 These towers are so arranged that they 

 may be cut out of the system for a short 

 time so they may be cleaned and refilled. 

 This is done from the top. The accumu- 

 lated liquors may be drawn from the bot- 

 tom by means of hard rubber cocks. 



One small room having a floor drain 

 and connection with the chemical vent is 

 set aside in the basement for the hydro- 

 gen sulphide generators. The floors, walls 

 and ceilings are of one piece of asbestolith. 

 This practise is followed in the storage 

 battery room on the same floor. 



A constant temperature room is con- 

 veniently had by selecting a small inside 

 room in the center of the building and 

 next the ground. It may be lighted by 

 electricity, and, in this way, compara- 

 tively slight changes of temperature will 

 be observed during the year. 



STORAGE BATTERY 



The principle advocated for storage-bat- 

 tery control may best be explained by out- 

 lining our system. Forty-eight cells are 

 provided, with a discharge rate of 60 

 amperes in one hour, and with 120 ampere 

 hours capacity on an 8-hour discharge. 

 The cells are permanently connected as fol- 

 lows : One battery of 8 cells, connected two 

 in series and four in parallel, giving four 

 volts and capable of discharging at the rate 

 of 60 amperes for 8 hours; two batteries 

 of 12 cells each, connected three in series 

 and four in parallel, giving 6 volts and 

 having the same discharging capacity as 

 the 4-volt battery; one battery of 16 cells 

 connected four in series and four in 

 parallel, giving 8 volts and yielding 60 

 amperes for 8 hours. All the batteries can 



