LABORATORY SUPPLIES AND CHEMICALS 



87 



2195 



2197 



CALORIMETER Parr's, for Gas, devised by 

 Prof. S. W. Parr, of the University of Illinois. 

 This instrument is constructed upon radically 

 new lines. A standard and an unknown gas 

 are burned side by side under identical con- 

 ditions. A ratio of values is thus established 

 in a manner which eliminates errors due to 

 radiation, metering, variable pressures, speed 

 of combustion, etc., etc. This is decidedly the 

 most accurate apparatus thus far devised for 

 the measuring of heat values of gases of all 

 types. Price $275.00 



2197 CALORIMETER, 

 American Junkers. 

 This apparatus is of 

 the same general de- 

 s i g n (embodying, 

 however, American 

 improvements), and 

 operates on the same 

 principle as the orig- 

 inal German Junkers 

 Calorimeter which 

 has been regarded by 

 gas experts as the 

 most satisfactory 

 calorimeter in use. 

 Calorimeter with all 

 improvements, inlet 

 and outlet water ther- 

 mometers in tenths 

 of a degree with 

 telescopic sights and 

 manufacturers' cer- 

 tificates giving cor- 

 rection factors, if 

 any, exhaust ther- 

 mometer, wet test 

 meter, complete with 



thermometer, wet regulator with pressure gauge, fine equal arm weighing bal- 

 ance, set brass weights in block, two copper pails, glass graduate for conden- 

 sation, twelve feet pure rubber tubing, correction table for temperature and 

 pressure, booklet on calorimetry, complete as shown in illustration $275.00 



2198 CARBONATE APPARATUS Barker. For determining the percent- 

 age of carbonates in limestone and other materials. 



The principle upon which the apparatus is based is that of a 

 hydrometer which takes account of the law that when an object (the 

 hydrometer) is immersed in a liquid, it is buoyed up by a force equal 

 to the weight of the liquid displaced by the object. In this apparatus 

 the carbon dioxide gas released by the sample decreases the weight. 

 The apparatus consequently rises in the water in which it is immersed, 

 recording on the graduated scale the percentage of carbonates from 

 which gas escaped. 



Every hydrometer is thoroughly tested before leaving the factory 

 and is accompanied by a certificate. 



BARKER CARBONATE APPARATUS, complete with Hydrom- 

 eter, jar, thermometer, graduated cylinder dropping pipette and one 

 pound of Hydrochloric Acid. 



Complete as described $12.00 



2198 Hydrometer only 9.00 



