I 



Misccllan ies. 385 



and from seven to eight days in winter, the pipes may be covered, 

 with an assurance of their solidity. 



In all the basins or reservoirs of the city, he used only this cement, 

 and tlie joints prove to be as tight as if cast iron had been melted 

 and poured into them, or as if the cisterns were made of glass. 

 They stand in no need of repairs. 



• He recommends this cement in all cases of hewn stone and otiier 

 solid works exposed to the weather, as in bridges, aqueducts, con- 

 duits, &;c. — Annahs des Mines. Tom. V. 3^ liv. 1829, 



38. Poiatoe Cheese. — ^In Thunngia and part of Saxony, a kind 

 of potatoe cheese is made which is very much sought after. The 

 following Is the recipe : select good white potatoes, boil them, and 

 when cold, peel and reduce them to a pulp with a rasp or mortar ; 

 to five pounds of this pulp which must be very uniform and homo- 

 geneous, add a pint of sour milk and tlie requisite portion of salt ; 

 knead the whole well, cover it, and let it remain three or four 

 days, according to the season ; — then knead it afresh, and place the 

 cheeses in small baskets, when they will part with their superfluous 

 moisture ; — dry them in the shade, and place them in layers in large 

 pots or kegs, where they may remain a fortnight. The older they 

 are the finer they become. 



This cheese has the advantage of never engendering worms, and 

 of being preserved fresh for many years, provided it is kept in a dry 

 place, and in well closed vessels. 



Other proportions of pulp and curdled milk are used, but tlie 

 above is preferred. — Bull. d^Enconr. Sept. 1829. 



39. On the supposed influence of magnetism in the phenomena of 

 Chemical combinations and crystallizations ; hy Prof. Erdmann. 

 From the discordant statements of Chemists with regard to the effects 

 of magnetism, on the oxidation of metals, crystallization of salts, 

 changes of color in vegetable tinctures, fee. Prof. Erdmann was in- 

 duced to examine the question with renewed care- He was per- 

 suaded that In the midst of so many disturbing causes, the question 

 could not be fairly decided by one or two experiments, which ap- 

 peared to have been the extent of the trials of those who had pro- 

 nounced a decision upon it. 



His magnetic apparatus appears to have been selected with much 

 care, and to have possessed a very adequate force. The greater 



