452 



Mr. W. Rosenhain on an 



Fisr. 1. 



ments which the author believes he has introduced into 

 the present form of calorimeter are principally connected 

 with the design of the various details of the instrument, a 

 detailed description will be necessary. 



The calorimeter-vessel is seen in 

 section in fig. 1. The brass vessel is 

 provided with two opposite windows, 

 which allow of a full view of the 

 interior of the vessel, so that the 

 progress of the combustion in the glass 

 combustion-chamber can be observed. 

 When in use the calorimeter-vessel 

 stands in a wooden casing, as a pro- 

 tection against radiation, and this 

 casing is provided with slots to corre- 

 spond with the windows in the vessel 

 itself. On the base of the calorimeter- 

 vessel is a lug which forms part of a 

 bayonet-joint by which the combustion- 

 chamber can be fixed in its place within 

 the calorimeter. 



Fig. 2 shows the combustion-chamber 

 in section, as seen in its place within the 

 calorimeter, while fig. 3 is a plan of 

 the same. Fig. 4 shows the combustion- 

 chamber in elevation, placed upon an 

 independent stand when removed from 

 the calorimeter. 



In fig. 2 (a) is the outer wooden case, (b) the brass 

 calorimeter-vessel, (c) the bayonet-joint. The combustion- 

 chamber itself is formed by a lamp-chimney — in practice a 

 Jena incandescent gaslight chimney is used — which is closed 

 at top and bottom by means of pairs of brass plates. In 

 each case the outer plate is movable, and can be brought 

 uear to the other by means of a screw ; a rubber collar is 

 placed between each pair of plates, and this makes a tight 

 joint with the glass when the screws are drawn tight *. 

 These are shown in section at Ui d) fig. 2. In each case the 

 fixed inner plate carries the various attachments. These will 

 be best understood by following the course of the oxygen 

 that flows through the chamber when in use. The gas enters 



* It is proper to state that the use of a lamp-glass for this purpose is 

 taken from Prof. Hudson Beare's instrument, but the author has substi- 

 tuted cylindrical gaslight glasses for the curved lamp-chimneys of the 

 former instrument, as the cylindrical glasses are made of more regular 

 shape. 



