506 



Mr. A. V. Harcourt. On the Limitation and [June 17, 



flask is cooled, the cork withdrawn, and more water poured in. 

 Finally, the acid liquid is neutralised with a standard solution of 

 ammonia. The capacity of the flask being known, and the temperature 

 and atmospheric pressure when it was filled having been noted, the per- 

 centage of chloroform in the mixture of chloroform vapour and air is 

 readily calculated. 



Fig. 3. Fig. 4. 



Many such analyses have been made in the course of this inquiry, 

 the flask being charged by taking the inspirations of ordinary breath- 

 ing through it for a couple of minutes. To save the operator from 

 being chloroformed, a flask of 25 litres capacity was interposed 

 between the smaller flask and the mouth (fig. 4). 



For the analysis of smaller quantities of air and chloroform than 

 will suffice for filling a flask by displacement of air, and for deter- 

 mining the total amount of chloroform dissolved by a liquid, such as 

 water or blood, another apparatus has been devised, the chemical 

 reaction being the same. It consists of a tube about 20 cm. in length, 

 and from 2 to 2*3 cm. in diameter, near the axis of which are two fine 

 platinum wires attached at one end to a stouter wire passing through 

 the glass, and at the other to the shorter arm of a lever turning upon 

 another wire at right angles to it which passes in through the side of 

 the glass tube ; the longer arm is weighted so as to fall when the wire 

 is elongated by heat and keep it stretched (figs. 5 and 6). When the 

 electric current, from wires attached to the platinum terminals outside 

 the tube, is turned off", the lever moves in the opposite direction. The 

 tube is set slightly aslope ; from its lower end a tube descends into a 

 flask, in which the hydrogen chloride formed is collected; at the upper 



