21 8 On the Determination of the [Sept. 



that it gave out the whole excess of its heat, and that it issued 

 out exactly at the temperature of the water of the calori- 

 meter. 



Hence we concluded that the heat given out by the gases was 

 equal to the excess of their temperature at their entry into the 

 calorimeter, such as we determined it, above that of the calori- 

 meter. 



§ IV. — Influence of the Tube which served to hect the Gases 

 upon the Temperature of the Calorimeter. 



An inconvenience attended the shortening of the intermediate 

 tube between the vapour tube and the calorimeter. The calori- 

 meter was heated directly by communication, independent of the 

 heat which it received from the gas which circulated in its inte- 

 rior. Now, as notwithstanding all the precautions that could be 

 taken to measure the heat received by the calorimeter from that 

 cause, some error might have been committed in the measure- 

 ment, it was necessary to make it as little as possible, that it 

 might be neglected without risk. On this account we employed 

 for that part of the tube a tube of glass, because that substance 

 is a bad conductor of heat. This tube, 0*8 inch in length, and 

 0*3 inch in diameter, was fixed to the apparatus in the following 

 manner, a little complicated in appearance, but very easily 

 executed, and having the great advantage of rendering lutes of 

 no use. 



The sides of our calorimeter are strengthened below by a 

 pretty thick plate of copper, about 0'8 inch high, firmly soldered 

 on, and covering nearly one-half of the circumference, as may 

 be seen in fig. 6, which represents a horizontal section of the 

 calorimeter through its lower part. This plate has fixed to its 

 two extremities two rods, b b, V b\ six inches long, and cut 

 half their length into the threads of a screw, upon which are 

 fixed the nuts, C, C. TTbe middle of this plate is pierced with 

 a hole, dd, which coincides with the orifice by which the inferior 

 part of the serpentine opens outwards. Round the hole is a flat 

 place, ff, destined to receive apiece of leather. 



Fig. 7 represents, the extremity of the tube filled with vapour, 

 which serves to heat the gases. This extremity is of copper. 

 The plate, EE, which terminates it, is pretty thick, and pierced 

 in its middle with an opening, I I, communicating only with 

 the interior tube, which contains the gas. This opening is sur- 

 rounded externally with aflat place, LI/, which receives a round 

 piece of leather. Immediately in the neighbourhood of the 

 terminal plate is the tube R S, which opening into the inside of 

 the vapour tube, allows the vapour and the condensed water to 

 escape, and carries them to a distance from the calorimeter. It 



