174 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



To remove the lining after the bomb has once been heated is a much 

 more difficult matter. It can be accomplished without lasting injury 

 to the platinum cup, but it necessitates a new flange. The flange is 

 bent up into line with the cup at three points, and at these points a 

 long piece of steel, about the size of a lead pencil and preferably ellip- 

 tical in cross section, with its entering end ground down to a blunt 

 wedge (with edges carefully rounded), is forced in between the lining 

 and the shell. The lining along three lines parallel to the axis of the 

 cylinder and extending nearly to the bottom is then pried in toward 

 the centre. This loosens the cup so that it can be removed by hand. 

 The lining can then be straightened out, the adhering iron and ferric 

 oxide removed by the use of melted acid potassium sulphate, any needed 

 repairs made, and a new flange put on. The removal of the lining would 



Figure 3. 



Figure 4. 



doubtless be made easier by making the shell much more tapering; but 

 this is very undesirable because it greatly increases, for a given volume 

 of the bomb, the difficulty of securing a tight joint at the cover. It is, 

 moreover, unnecessary, because if these instructions are followed care- 

 fully there should be no need of removing the lining after it is once 

 finally in place. 



A hole is drilled in the lining at the bottom so as to correspond with 

 the hole in the steel shell. It is then best to close this hole temporarily 

 with the steel piece shown in Fig. 3, using a lead washer under the V- 

 shaped ridge for packing. Then, in order to bring the lining into per- 

 fect contact with the shell and at the same time to test it for possible 

 faults, the lower part of the bomb is connected by means of the auxiliary 

 cover shown in Fig. 4 with a Cailletet pump or its equivalent, — a water 

 reservoir being interposed between the pump and bomb so as to force 

 water instead of oil into the bomb. For this testing of the lining a 



