KROEKER'S CALORIMETER. 



73 



The apparatus has been used with success in making the 

 very numerous determinations made by Atwater on the heats 

 of combustion of food-products and other allied organic sub- 

 stances. 



KROEKER'S CALORIMETER. 



Kroeker has recently modified the bomb, making two in- 

 let channels instead of one. By this means he has a current 

 of oxygen gas passing in at one opening and waste gases 

 passing out at the other. It can thus be used for the same 

 purpose that a Junker calorimeter is used, and it is claimed 

 with just as satisfactory results. 



The cylinder (Fig. 26) is bored out of a piece of Martin 

 steel, and has a closely-fitting screw-plug for cover, the depth 

 of the screw joint being 25 mm. The walls 

 of the cylinder are 10 mm. thick; external 

 diameter, 72 mm. ; internal diameter, 52 

 mm. ; height, 120 mm. ; contents, 200 cc. 

 It has four small legs on the under side, 

 which support it and keep it entirely sur- 

 rounded by the water of the bath. The 

 entire inside surface is enameled, or prefer- 

 ably platinized. The fuel, in the form of 

 compressed cylinders weighing one gram, 

 is put into the carrier, ignited as usual, 

 and the combustion gases collected and 

 examined. 



He also has a method of heating the 

 calorimeter bomb in an oil-bath so as to 

 expel all the water of combustion and hy- FlG 2 6. KROEKER 

 dration. He thus obtains data for cor- CALORIMETER. 

 rections due to the usual method of determining the water, 

 i.e., considering the water as condensed. 



