CENTRAL SCIENTIFIC CO., CHICAGO, TL S. A. 



403 



No. 10418. 



No. 10420. No. 10422. 



No. 10436. 



No. P5101. 



THERMOSTAT BATH, Aquarium Type, Continued. 



laising or lowering the mercury level. The capacity of the steel tubes and the diameter of 

 the capillary are so proportioned as to secure a regulation of 0.005C., or less, which is more 

 sensitive than a Beckmann thermometer. To eliminate vibration of the mercury surface in 

 the capillary chamber and prevent sparking, the thermo-regulator is suspended by two 

 springs. The thermo-regulator is in circuit with our sensitive iron clad relay, of the solenoid 

 type with multiple contacts, the opening and closing of which makes and breaks the current 

 through the regulating units. 



The entire design of the bath has resulted from actual laboratory experience throughout 

 many years with baths of various makes, and we have no hesitation in stating that it is 

 superior in design and in effectiveness to any other type. The small space taken up by the 

 heaters, regulator, stirrer and cooling coils, together with the absence of any grating or par- 

 tition, leaves the entire inside space available for use. Complete as described with four heat- 

 ing units, thermo-regulator, relay, turbine stirrer with motor for operation, constant water 

 level device and drain, two nickel-plated brass support rods with two clamps each, and five 

 feet of cord and separable attachment plug. 



Length, 61 em. Height from floor, 80 cm. 



Width, 61 cm. Capacity, 225 liters. 



Depth, 61 cm. 



No A B C D 



A.C. D.C. 



For volts 110 220 110 220 



Each $277.50 280.00 275.00 277.50 



10410. THERMOSTAT BATH, Aquarium Type, DeKhotinsky Electrically Heated and Regulated, same 



as No. 10408, but larger, with same equipment. 



Length, 71 cm. Height from floor, 80 cm.- 



Width, 70 cm. Capacity, 300 liters. 



Depth, 61 cm. 



No A B C D 



A.C. D.C. 



For volts 110 220 110 220 



Each 302.50 305.00 300.00 302.50 



10411. ROD CLAMPS for use with Xos. 10408 and 10410 each 1.25 



For other THERMOSTATS, see Water Baths. 



10418. TRANSFERENCE TUBE, Washburn, for the study of hydration of ions, etc. Complete as illus- 

 trated with two stop-cocks with bore equal to that of the tube, ground in glass plugs at the 

 ends, ground joint in the middle and sealed on tubes for obtaining samples to be analyzed, 

 with ground in stoppers. Without electrodes. (See Journal of American Chemical Society, 



Vol. XXXI, for 1909, page 322) 18.00 



VAPOR DENSITY APPARATUS, see general heading Vapor Density Apparatus. 

 10420. VISCOSITY PIPETTE, Drucker, with glass stop-cocks. Time of outflow, 80 to 100 seconds 5.00 



10422. VISCOSITY PIPETTE, Ostwald, with time of outflow 80 to 100 seconds 1.25 



F5101. VOLTAMETER, Copper, new construction. Consists of a glass jar in which are suspended 

 three copper plates, two loss plates and one gain plate, each of about 40 square centimeters 

 area. These plates are held by an ingenious clamping device and their construction is such 



that they may be handled without touching with the fingers 4.50 



F5102. VOLTAMETER, Silver, same construction as No. F5101, with detachable silver plates.. 9.00 

 10436. WHEATSTONE BRIDGE for Conductivity Measurements. Extended Coll Type, as developed 

 at the University of Illinois. The bridge is of the usual slide wire form with a half meter 

 scale graduated on the upper half from 475 to 525 cm and on the lower half from to 50 

 cm in 0.1 cm divisions. A wire of very low thermal coefficient but of high resistance is 

 stretched over the scale, and a sufficient amount is wound on two spools, placed at the ends, 

 to make 1000 cm of total length, exactly divided as to resistance. By means of removable 

 plug contacts, the bridge may be used either as a half-meter or as a ten-meter bridge. In 

 this way the resistance of a solution may be approximately determined on the half -meter 

 scale, the plugs then removed and the exact point determined on the ten-meter scale. By 

 using this bridge, readings can be readily made with an accuracy of 0.01 of 1 per cent. 30.00 

 For other WHEATSTONE BRIDGES, see general heading, Electrical Instruments. 



