Scientific Intelligence. — Jrt.<t. 189 



its propagation was entirely checked by intense cold, ceasing 

 each year about the 15th of* October, and breaking out again in 

 the month of April. Humboldt, who made some observations 

 on the paper, said that he was of opinion it was not imported 

 into Europe by caravans, which are all subjected to a strict 

 quarantine ; and that the Russian army brought it hack with 

 them from Persia ; and that its extension into southern Europe 

 is very probable from the movements of large bodies of men to 

 the western frontier of the Russian empire. To those interested 

 in the nature of this terrible disease, we recommend, as the best 

 treatise on the subject, that published by Dr Alexander Turn- 

 bull Christie. 



ARTS. 



26. Size for Illuminators^ Artists, 4'^. — Four ounces of 

 Flanders glue, and four ounces of white soap, are to be dis- 

 solved on the fire in a pint of water, two ounces of powdered 

 alum added, the whole stirred and left to cool. It is to be 

 spread cold with a sponge or pencil on the paper to be prepared, 

 and is much used by those who have to colour unsized paper, as 

 artists, topographers, &c. — Bull. Univ. 



27. Manufacture of Charcoal. — A new process, recommend- 

 ed in the Journal des Forets, for this purpose, is to fill all the 

 interstices in the heap of wood to be charred, with powdered 

 charcoal. 



28. Potash obtained commercially from Felspar. — According 

 to M. Fuchs, this important alkali may be extracted from mi- 

 nerals containing it, by the following method ; — They are to be 

 calcined with lime, then left some time in contact with water, and 

 the liquor filtered and evaporated. M. Fuchs says, he has thus 

 obtained from nineteen to twenty parts of potash from felspar, 

 and from fifteen to sixteen from mica, per cent. — BrancTs Jour- 

 nal, No. I. New Series. 



29. Improvements in Printing — It is well known that of late 

 years a vast additional power has been given to the art of letter?, 

 press printing, by means of machinery. For speed, the newly- 

 invented printing machines, when compared with the manual 

 presses, are to printing what the power-loom is to weaving; 

 and, accordingly, they are of great utility in all establishments 



