NOVBMBEB 13, 1908] 



SCIENCE 



675 



be discharged so as to give 240 amperes in 

 one hour. 



The four battery systems are connected 

 by cables to five bus bars on the distribu- 

 ting board in the electrolytic room, each 

 bar being provided with 24 distributing 

 sockets. The ends of the batteries are con- 

 nected in series so that the differences of 

 potential between the bars are, respectively, 

 4, 6, 6 and 8 volts, and 24 volts between 

 the end bars. By this arrangement any 

 desired voltage from 4 to 24 volts may be 

 obtained. Connections are made from the 

 distributing sockets to any current outlet 

 in any part of the laboratory by means of 

 plugs connected by a flexible cable pro- 

 vided with a fuse. Current is supplied 

 to the user at the voltage and maximum 

 current strength asked for. It is possible 

 to supply about 60 outlets at a time with 

 any voltage up to 24 volts. On disconnect- 

 ing any allotted cells, the user has to state 

 the approximate number of ampere hours 

 taken from them. A record is kept of 

 this for each battery, and it is thus easy to 

 tell when a battery requires charging. 

 The cells in each battery being used up 

 at the same rate, any single cell is pro- 

 tected from being run down by a careless 

 user, and all cells in a battery are in a 

 comparable state. 



The charging leads from the dynamo 

 are led direct to the electrolytic room and 

 connected to two sockets, and the charging 

 connection to any set of cells is made on 

 the distributing board, the battery room 

 only having to be entered to inspect the 

 cells. Current can also be taken direct 

 from the dynamo from these sockets. Two 

 plugs on the distributing board are con- 

 nected to traveling cables in the battery 

 room, so that any desired number of cells 

 can be permanently assigned for specific 

 purposes, and the condition of each cell 

 investigated. The switchboard is of the 

 simplest construction, yet it offers the most 



flexible arrangement known to the writer. 

 It is essentially a marble slab supported 

 vertically with brass-lined equidistant 

 holes. A pair of holes leads to each outlet 

 in the laboratory and is numbered. At the 

 bottom are five rows of similar holes lead- 

 ing to the sets of cells in the battery room 

 referred to. The connections are made by 

 two flexible cables. 



ELECTRO-ANALYSIS 



Knowing of no better arrangement, the 

 room for electro-analysis was copied after 

 that of Professor Edgar F. Smith, of the 

 University of Pennsylvania. There are 14 

 places containing voltmeters of 50 volts in 

 half-volt divisions, and four voltmeters 

 of 150 volts in half-volt divisions. On 

 each side of these are two ammeters, one 

 reading from to 1 ampere in 100 ampere 

 divisions and the other from to 25 

 amperes in one fifth ampere divisions. 

 The rheostats for these instruments are of 

 the enamel type, having a total resistance 

 of 172 ohms and divided into 51 steps 

 arranged in geometrical progression. 



STOREROOMS 



The arrangement of the stock rooms pre- 

 sents interesting problems which are met, 

 as a rule, in many small stores where com- 

 pactness affords limited opportunity for 

 roominess. As many drawers of various 

 sizes, for different purposes as can be, 

 should be built as part of the cabinet work 

 up to about forty inches from the floor. 

 Upon this can be constructed two kinds of 

 shelves. First, ordinary wooden bottom 

 shelves, preferably movable, for holding 

 chemicals in bottles; second, wire-bottom 

 shelves for holding glassware. Glass tubing 

 and rods, placed on end, are well taken care 

 of by upright partitions about 15 cm. apart 

 and 25 cm. deep. It is desirable to have 

 suspended over the outside of the last men- 



