74 



CALORIFIC POWER OF FUELS. 



WALTHER-HEMPEL BOMB. 



Two modifications of the Berthelot bomb are known 

 under this name. The larger one does not differ in enough 

 points to make a special mention of it necessary ; but the 

 smaller one, the one intended for use in analysis, is worthy of 

 description. 



It consists of a small cylinder of 33 cc. capacity (Fig. 27), 

 bored out of white cast iron and enameled inside. The walls 

 are 2 millimetres thick, and it is strong enough to resist eight 

 times the pressure generally used. The cover 

 is fastened on by means of a screw-clamp, 

 and through it passes the slanting opening a, 

 having the electric wire-carrier insulated by 

 a caoutchouc sheath. To the wire at the end 

 of this sheath is attached a platinum wire for 

 kindling the combustible. On the opposite 

 side of the cover is the oxygen tube d. The 

 platinum wire c is attached to the under side 

 of the cover, and supports the combustible- 

 carrier and its little fire-clay cylinder e. 



The fuel is made into small cylinders by 

 compression, put into the fire-clay cylinder, 

 and ignited by the electric spark. The 

 products of combustion are collected and 

 weighed or measured : the water partly in the 

 bomb and partly by means of a calcium chlo- 

 ride tube ; the nitric and sulphuric acids are 

 determined by titration with y^j- normal alkali, 

 and afterwards separated if deemed necessary. It is claimed 

 to be capable of use the same as a large one. A full descrip- 

 tion of it is given in the Berliner Bericht for January, 1897. 



FIG. 27. 

 WALTHER- 

 HEMPEL BOMB. 



