
fill the bomb until the manometer indicates a pressure of twenty | 
atmospheres. The oxygen is then cut off and the bomb valve. ’ 
closed. The operation is extremely simple and rapid. In 
recent tests of the bomb valve, manometer coupling, and con- 
nections, a pressure of 33 atmospheres was left on for thirty-six 
_ hours without the slightest indications of a leak. 
The graduations of the manometer enable the operator to 
ascertain when the supply of gas is nearly exhausted. When 
the pressure falls to thirty or twenty-five atmospheres another 
cylinder of oxygen is ordered. 
It is expected that a later article will discuss methods for 
determining the hydrothermal equivalent, describe methods of 
manipulation which experience has indicated as desirable, and 
give the results obtained in the combustion of various materials. 
It is also hoped that there may be opportunity to answer ques- 
tions received from any sources regarding the use of the appa- 
ratus for determining the heats of combustion of fuel materials, 
as coal and gas. 
Meanwhile it may be proper to say that the apparatus has 
proven very satisfactory in the hands of a considerable number 
of chemists in different parts of the United States. Nearly all 
of the determinations of the heats of combustion of food mate- 
rials, with which we are familiar as lately published in this 
country, have been made by the use of this apparatus. 

IMPROVED FORMS OF BOMB CALORIMETER. 217, 
Lee 
