SSi SCIEJilTlFIC NEWS* 



Mr. Ton Humboldt. Dr. C. ^. Bucholz, having attempfe4 

 to analyse a sulphate of zinc containing copper in thp 

 mode proposed by Mr. Vauquclin, has proved its instifli- 

 eiency. He immersed a slip of zinc in a solution o^ the 

 sulphate, and found, that the zinc, instead of precipita- 

 ting metallic copper, acquired a blackish coating, ivhich, 

 when separated, dried with blotting pi|.per, and rubbed with 

 an agate burnisher, had the colour and brightness of brass- 

 Defence of for- A treatise on the Defense of fortified Places, composed 

 aces. ^^ order of the Emperor, for the Instruction of the Pupils 

 of the Corps of Engineers, by Mr. Carnot, is a work of 

 considerable importance in the military art. In an ap- 

 pendix he strongly recommends to the besieged, to fire 

 howitzefs loaded with grapeshot, or musket balls, at an 

 elevation of 45°, when the enemy have made their ap- 

 proaches within a certain distance. They may thus lire 

 from behind the ramparts, without being exposed; and 

 their shot will do more execution, not being stopped by 

 the cncm)^'s works. This is now made a part of the 

 French artillery exercise. 

 New Encyclo- Jjj the beginning of last year was announced at Paris a 

 ^^*** prospectus of an " Instructive Collection of all the theore- 



tical and practical Truths hitherto discovered in Natural 

 History, Physics, Chemistry^ Medicine, Surgery, Agri- 

 culture, Arts and Trades, and Domestic Economy, sub- 

 jected to fresh Examinations, verified by new Observations, 

 and {Jonfirmcd by new Experiments." The work is to be 

 illustrated by upward of a hundred and fifty thousand 

 plates, many of them coloured, representing accurately all 

 the mineral substances that can be delineated, all known 

 plants and animals, all the machines, inventions, instru- 

 ments, and tools hitherto, contrived, in France or othe^: 

 countries, with portraits of persons who have distinguished 

 themselves in the arts or sciences. It is to be the joint work 

 of a great number of literary men and artists of the various 

 parts of Europe; and is to be composed ia four separate 

 languages, French, English, Italian, and German, by new 

 methods, the object of which is to render its execution 

 equally prompt and perfect, and to enable persons of the 

 smallest fortunes to procure this useful collection at a 



trifling expense. 



INDEX. 



