[ 321 ] 



LIII. Description of an improved apparatus for the De- 

 composition of Potash and Soda. By William Johns, 



Esq, 



To Mr. TillocL 



Sir, J. HE publicity of the Philosophical Magazine in- 

 duces me to transmit for insertion the following account 

 of some successful attempts to repeat the brilliant experi- 

 ments of professor Davy^ in the decomposition of potash 

 and soda, an a more oeconomical plan than has before been 

 suggested*, and which I hope will enable your readers to 

 obtain potassium, &c. for their use at a very moderate ex- 

 pense, 



I am yours, &c. 

 April 16, 1810. William Johns, 



No. 3, Orford Row, Kent Road. 



EaiTLv in the present year, wishing to decompose potass 

 with the bent gun-barrel as is done at the Royal Institution, 

 and not enjoying the ample resources of its excellent che- 

 mical professor; it became a desideratum to construct an 

 apparatus, which might serve for the repetition of the ex- 

 periment, instead of cutting the gun-barrel in pieces, as ia 

 the method before in use, — a practice attended with consi- 

 derable expense, and which could not but check the ardour of^ 

 those who are fond of chemical researches, and prevent the 

 frequent repetition of the experiment : the disappointment 

 resulting from an unsuccessful experiment being always 

 Ttruch heightened when accompanied with the loss of an 

 expensive apparatus. 



Having succeeded in constructing an apparatus simple 

 and efficient, and which has met the approbation of several 

 eminent chemists, I herewith send you a drawing and de- 

 scription of it. 



The apparatus consists of a common gun-barrel wTth 

 one bend, and one of the ends inclining downwards a little. 

 The inclining straight part is cut off from the bent portion 

 at about three inches distance, is ground into it, beings 

 made to fit air-tight. Underneath is a small thin iron tube 

 open at both ends, made a little conical, which when the ap- 

 paratus is taken to pieces is placed within the interior of the 

 straight piece, one half of it going into this part; the other 

 will be received in the opposite part, when the apparatus is 

 again put together. This small tube is to collect the potas- 



♦ See Phil. Mag. vol. xxxii. p. 276. 

 .Vol, 35, No. 145. May 1810. X slum 



