ON SOME BLOWPIPE'REACTIONSJ 253 



borax or pliosphor-salt on a loop of platinum wire, and bisulphate of 

 potash, in several successive portions is added to the fused bead. The 

 latter is then shaken off the wire into a small porcelain capsule, and 

 treated with boiling water. A bead of alkaline sulphide is next 

 prepared by fusing some bisulphate of potash on charcoal in a reduc- 

 ing flame, and removing the fused mass before it hardens. A portion 

 of the solution in the capsule being tested with this, a yellow preci- 

 pitate will be produced if cadmium be present. The precipitate can, 

 be collected by decantation or filtration, and tested with some carb- 

 soda on charcoal. This latter operation is necessary, because if either 

 antimony or arsenic were present, an orange or yellow precipitate 

 woxdd also be produced by the alkaline sulphide. By treatment 

 with carb.-soda on charcoal, however, the true nature of the preci- 

 pitate would be at once made known. 



v.— ON THE SOLUBILITY OF BISMUTH OXIDE IN CAEBONATE 

 OF SODA BEFOEE THE BLOWPIPE. 



Neither in the treatise of Berzelius, nor in the more modern and 

 advanced work of Plattner, is any reference made to the behaviour 

 of oxide of bismuth with carb.-soda in an oxidating flame. In 

 Plattner's " Tabellarische Uebersicht des Yerhaltens der Alkalien, 

 Erden, und Metalloxyde fiir sich und mit Keagentien im Lbthrohr- 

 feuer," whilst oxide of lead is stated, correctly, to be soluble in carb.- 

 soda in an oxidating flame, the reference to oxide of bismuth is, 

 simply, that with carb.-soda on charcoal it becomes immediately 

 reduced to metallic bismuth ; and none of his translators seem to 

 have thoiight it necessary to supply the omission. In Hartmann's 

 tabular " Untersuchungen mit dem Lothrohr," in the handy little 

 work of Bruno Kerl (" Leitfaden bei qualitativen und quantitativen 

 Lothrohr-Untersuchungen"), in the " Lothrohr-Tabellen " of Hirsch- 

 wald, and all other blowpipe books that I have met with, the same 

 singular omission occurs. This seems to bear out very forcibly the 

 somewhat cynical adage that "books are made from books." To 

 supply the omission, it may be observed that bismuth oxide dissolves 

 in carb.-soda very readily in an oxidating flame, if the supporting 

 agent be platinum wire or other non-reducing body. The glass is 

 clear yellow whilst hot, but on cooling it assumes an orange or yel- 

 lowish-brown colour, and becomes pale-yellow and opaque when cold. 

 As regards their solubility by fusion in carb. soda, metallic oxides 



