Faraday dh Alkatim Properties. 317 



A strong solution of chloride of manganese seems feebly but 

 evidently alkaline to tumeric paper. 



It may be supposed, that with many of these substances, the 

 effect is produced principally by the acid present, inasmuch as 

 they were all more or less acid to litmus, and it has been 

 shewn that these bodies, especially nitric acid, have this power. 

 But the very slight excess in some of them, as in the salts of 

 iron, zinc, manganese, Sfc. ; and the greater effect produced 

 by farther dilution, as with bismuth and antimony, shew that 

 the whole substance must act : for if it be considered due to the 

 acid alone, it is not, in the first case, of sufficient quantity, and 

 in the second, it would be diminished by dilution. 



It is probable that, if the tints produced be compared exactly 

 with those occasioned by alkalies, slight differences might be 

 perceived among some of them ; or that, if the properties of 

 the altered colouring matter were examined, they would be 

 found different with the different substances, as M. Desfosses * 

 has shewn with regard to boracic acid and other acids ; but my 

 object has not been to trace these changes as far as possible, 

 but merely to shew their gentx'al appearance ; to guard against 

 any deceptive conclusion with respect to solutions tested by 

 tumeric ; and to call attention to the distinguishing characters of 

 acids and alkalies. 



Art. X. Proceedings of the Uoxfal Society. 



The following papers have been read at the table of the Royal 

 Society since our last report. 



A/r^frS ^^' Contributions towards the anatomy of whales, by 

 Mr^ illiam Scoresby, communicated by Sir Everard Home.bart., 

 V. p. K. S. 



April 18. On the changes that have taken place in the decli- 

 nation of some of the principal fixed stars, by .lohn Pond esa 

 Astronomer Royal, F. R. S. " ' ^' 



Extract of a letter from Captain Sabine to the President. 



Some observations on the buffy-coat of the blood, by .John 



* Vol. xi. 40J. 



V..f.. XIII. z 



