Miscellanies. 1 97 



vessel is coated with magnesia, and a black spot appears where the 

 metal was, which, the author takes to be silicium, because it is not 

 removed by boiling acids. 



The metal does not unite with sulphur by fusion, but inflames in 

 chlorine. 



Its solution in sulphuric acid, gives by evaporation crystals of pure 

 sulphate of magnesia. It is thus proved that magnesia contains a met- 

 al possessedof properties well worthy of attention. — Annates de Chi- 

 mie. 



27. On crystalizahle acetic acid ; by C. Despretz. — The method 

 by which crystalizable acetic acid is made has been kept secret. 

 After various trials, I obtained it in very fine crystals by heating a 

 mixture in proper atomical proportions of acetate of lead, melted 

 and dried, and boiled sulphuric acid, (203.4 parts of the former, and 

 61.4 parts of the latter.) All the manufacturing chemists that I have 

 consulted, inform me that they procure their acid from a factory 

 which has not made the process known. 



Anhydrous acetates ought necessarily to produce the same result 

 as acetate of lead. — Ann. de Chimie, Fev. 1830. 



28. On the separation of antimony from tin; by Gay Lussac. — 

 The alloy of the two metals being dissolved in hydrochloric (muri- 

 atic) acid, in excess, a plate of tin is dipt into the solution, and it 

 becomes immediately covered with antimony in black powder. The 

 precipitation is not complete in the cold, at least, a long time will be 

 required for it ; but by heating it in a vapor bath it will soon be com- 

 pleted, provided an excess of acid be kept up in the liquid. The 

 antimony may be afterwards perfectly washed and dried on a water 

 bath. — Ann. de Chim. et de Phys. 



29. Method of destroying the loorms which attack fruit trees, by M. 

 De Thosse. — Unforeseen circumstances often lead to useful discove- 

 ries. One fact or discovery leads to another, and may form eventu- 

 ally a succession which constitutes the chain of our knowledge. 



Agriculture is one of those pursuits in which theory should be 

 combined with practice, and those who follow it ought to be duly 

 sensible of the many things which, in its various branches, it is still 

 desirable should be found out. 



