1815.] On Pi/rophorus, and the making of Potassium. 351 



foundery, I had the opportunity of making my potassium there, as 

 I could apply the blast from the smelting furnace to my apparatus, 

 and then I got it in considerable quantity. 1 generally laid two 

 barrels parallel to each other through the furnace, and thus got once 

 nearly two ounces ; but I repeat, that without being able to give a 

 very high degree of heat, it is not worth while going about making 

 potassium, as the quantity obtained will be very trifling. For a lute, 

 to cover that part of the barrel which comes in immediate contact 

 with the fire, I tried mixtures of pure clay wdth sand in ditferent 

 proportions ; but none of them answered my purpose so well as the 

 clay by itself, which is found near Moscow, and used for crucibles 

 all over Russia ; it is known in commerce by the name of JNIoscow 

 clay. Using this clay, I could give almost any degree of heat that 

 can be procured from charcoal (which I always used, we having no 

 coal in St. Petersburgh), witliout melting the barrel. The open 

 ends of the barrels were placed under oil in one small bason ; and 

 after the operatipn was finished, I simply corked thenj, in order to 

 prevent the air getting in, till I had cut otF the under parts of the 

 barrels, in order to obtain the potassium also which was collected 

 there. This latter is, as I have said before, always less fusil)le, and 

 alloyed with iron, whereas the other, which does not remain for any 

 time in contact with the iron barrel, runs down into the oil, which 

 absorbs the oxide, which might be on its surface, forming a soap 

 with it. This potassium was the purest I ever obtained. 1 used to 

 keep it in small glass tubes, in which I pressed it close towards the 

 inside of the glass, and the tubes being hermetically sealed. 



I am, dear Sir, yours most faithfully, 



iitus^uu:, March 15, 1815. J. HAMJiL, M. D. 



Article VIII. 



Desiriptlon of a Mai hi ue for the speedy Separation and Manifac- 

 turt if Farina or Flour from Potatoes, and for various Oiserva- 

 lions relative to the A\'ccssily of encouraging an extended Groivth 

 of Potatoes, and for their Applieulions, in various States, to 

 make Sea Biscuits, Bread, Pastry, &tc. By John Wliately, 

 Eiq. of Cork. With a Plate* 



It is naturally the first object, and forms the primary duty of a 

 well-regulated state, to provide its mcml)ers with a sufficient 

 quaiility of good food. The greater aic the advantages, and the 



• I'roen ilie Traii»:irl!oii<i of the Socjply tpr t'lp Mnrixirii-^pmrnl of .\ri<, Mitnu- 

 f.ii'li)ic>, and C'uiiiuicrcc. Tlie letiturgulii uiodul vvuiNutiii lu Mr. VVIiutd^ I'ur tliij 

 tiiteuliou. 



