212 



EXPEKTMENT STATION RECORD. 



which in the Shuttle worth apparatus is attached to the tube introduc- 

 ing- air into the crucible, and in the Tucker apparatus extends down 

 through the inlet tu])e. 



The Tucker apparatus has the advantage over the Shuttleworth 

 apparatus of simplicity of construction and ease of operation. Again, 

 tlie cover of the Shuttleworth apparatus is complicated, and forcing the 

 air through is less satisfactory than drawing it through, as in Tucker's 

 apparatus. The conical form of the crucible of Tucker's apparatus is 

 also preferable, permitting the heat to be applied more uniformly. 



Fig. 2. — Tufkcr iipparatiis for as?h determination. 



With this apparatus, straw, leaves, and potatoes are incinerated in 

 the course of two hours, the charring occupying about 1^ hours, and 

 the completion of the incineration in a current of air requiring not 

 more than a half hour. 



H. Wislicenus^ has recentlj' described an apparatus which embodies 

 the principle of the Tucker apparatus, but consists only of a platinum 

 cover which may be adapted to dishes and crucibles ordinarily" found 

 in laboratories, thus doing awa}" with the special crucible. 



Another form of incinerating apparatus is the Berthelot bomb, in 

 which the substance is burned, b}' means of an electrically heated wire, 

 in oxygen under 25 atmospheres pressure. This apparatus has the 

 advantage of excluding every possible loss, and is absolutely closed 



^Ztschr. Analyt. Chem., 40 (1901), No. 7, p. 441. 



