442 POTASSIUM. 



an aperture in the side-wall of the furnace, and enters a re- 

 ceiver of a peculiar construction required to condense the po- 

 tassium, which distils over. This receiver is composed of two 

 separate copper cylinders or oval boxes, hard soldered, si- 

 milar in form and size, which are represented in section in 

 figure 46, the one b nd being introduced within FIG. 46'. 

 the other g h k, and thus forming together a 

 vessel of which b n d is the cover. It will also 

 be observed that b n d is divided into two 

 cells by a diaphragm i, of the same length as 

 the cylinder, and descending with it to within 

 two inches of the bottom h of g h k. A ribbon 



of copper g is soldered around b n d, so as to form a ledge, 

 which is seen in both figures, and serves as a support for a 

 cage of iron-wire c d, placed over the receiver daring the distil- 

 lation, to hold ice, and also to shed the water from the lique- 

 faction of that ice, which falls into a tray p below, and flows 

 off by the tube /. The cover has also two short copper tubes 

 d and b y of which the copper of b is notched so as to clasp 

 firmly by its elasticity the tube b from the iron bottle, which 

 is fitted into it. The other tube d, which is exactly opposite 

 to by is fitted with a cork, and the diaphragm i has a small 

 hole in it to allow of a rod being passed through b and d. 

 In the same part of the apparatus is a third opening, to which 

 a glass tube x is fitted by a cork, for the escape of uncon- 

 densible gases. The receiver is filled to about one-third with 

 rectified petroleum, a liquid containing no oxygen, so as (o 

 come near to, but not to cover the bottom of the partition i. 

 The length of the bottle is 1 1 inches, its width 4, and the other 

 parts of the apparatus are designed upon the same scale. 



Potassium and carbonic oxide gas are the principal products 

 of the decomposition of the carbonate of potash, but other 

 substances besides these are found in the receiver, namely, a 

 black mass very rich in potassium, some oxalate arid croconate 

 of potash and free potash, with a portion of charcoal powder 

 carried over mechanically. Part of these products appear to 

 be formed, after the reduction of the potassium, by the mutual 

 reaction of that metal, carbonic oxide and petroleum. The pro- 

 cess is found to succeed best when the iron tube b is so short 

 that it can be maintained at a red heat through its whole length 

 during the operation, while the receiver is kept at a very low 



