S.CIENTIfIC NEWS. ^^Oil 



It is not among minerals alone that fufafiances are found 

 which are graduall)' oxided, and by intermediate degrees. 



Indigo affords an inftance that vegetabie and animal bodies Vegetable and- 

 offer fimilar proofs ; for any folution of indigo (excepting the f^||^^ f°mWar 

 fulphate of indigo) will, on difoxidation, or on having its oxi- eafes with mine- 

 gen reftored, pafs through all the degrees of (hade, from oxilttn!''^"^' 

 blueifh green to very yellow olive, preferving in the mean 

 time the fame quantity of indigo in folution. The beauty and 

 lability of the colours, either for dying or painting, will 

 chiefly depend on the degree of oxidation. On fome other 

 occafion, Sir, I fliall write to you more amply on this fubjecl. 



SCIENTIFIC NEWS. 



Memoires de V Academic imperudt des Sciences, &fc. Memoirs of 

 the imperial Academy of Sciences, Literature, and fine Arts^, of 

 Turin, for the Years 12 and 13, 2 Vols, Quarto. 1805. 

 Turin, 



W HEN the Royal Academy of Turin afluraed the name Memoirs of tJ^ 

 of Imperial, in confequence of Piedmont being annexed to J^^'^^i g 'i^' 

 France, the number of academicians was increafed, to form a ences, &c. of 

 new clafs, that of literature and the fine arts. Of the two Tunn. 

 volumes publiftied, one is appropriated to the labours of this 

 clafs, the other to that of the phyfical and mathematical 

 fciences. 



The latter is compiled by the fecretary, Mr. Vaflali Eandi", 

 whofirfl mentions the changes ihathave taken place in the lift 

 of academicians, next the various papers that have been read at: 

 their meetings, and then the books and other articles preiented 

 to the fociety. Thefe lifts are followed by a well written ac- 

 count of the labours of the academy up to the year 1805, 

 which occupies 250 pages.. After this follow the different 

 memoirs. 



1. Defcription and ufe of a new portable barometer, for 

 meafuring heights and depths, with obfervations made with 

 this inftrument in the circles of Turin and Saluzzo. This 

 inftrument, of which a figure is given, was invented by the 

 fecretary ; who has fubjoined to his paper fome very cuxious 

 hiftorical notes on the places where his oWervaiions wer* 

 made. 



^ 2, Account 



