2S0 Notices respecting New Books. 



heat of the mixture, which sometimes swells so as to run 

 over the vessels, causes the succinic acid to disappear en- 

 tirely. 



However minute the means I employed to extract the 

 succinic acid may appear, I thought it necessarv to describe 

 them. I first conceived the idea of separating it with a 

 card : this process succeeded prettv well ; but in this case one 

 is exposed to the danger of being burnt. I employed with 

 more advantage a spoon of tinned iron, which is different 

 from the usual form only in being semicircular, not so con- 

 cave, and proportioned to the size of the vessel. It termi- 

 nates behind in a thin plate of iron, which, exceeding the 

 edge by some lines, represents a sort of band, from which 

 arises, at right angles, a handle of the same substance, 

 fifteen inches in length. This form appeared to me most 

 convenient; first, because, by applying it exactly against 

 the sides of the vessel, it prevents the salt, which is de- 

 tached by instantaneously removing it, from being mixed 

 with the fused amber; secondly, because it offers to the artist' 

 the means of operating, without being so much incommoded 

 by the vapours disengaged from the matter. 



It results from what has been said, that artists v;ho pre- 

 pare amber varnish may in future, without making any 

 change in the apparatus or in their process, obtain a consi- 

 derable quantity of succinic acid, which, though hitherto 

 confined to medicinal purposes, may soon be rendered useful 

 in the arts. Some trials already give reason to hope that an 

 alcoholic solution of it may be employed for imitating the 

 colour of certain valuable kinds of wood. 



XLVIII. Notices respectiiig New Books. 



T)ie Painter and Farnisher's Guide; or, A Treatise, loth ifi 

 Theory and Practice, on the Art of making and applying 

 Varnishes; on the different Kinds of' Painting; and on 

 the Method nf preparing Colours, loth simple and com- 

 pound, &'c. Bi/ P. F. TxNGRV, Professor of Chemistry, 

 &c. in the ykadeniy of Geneva, 8vo. 540 Pages. Kears- 

 Icy, Fleet-street. 



\ T E have perused this work with great satisfaction; it 

 contains much new, useful, and interesting information on 

 the difierent subjects which it embraces, and cannot fail to 

 be highly serviceable to artists. We think the publisher has 



rendered 



