TO OUR READERS AND CORRESPONDENTS. 



Communications have reached us from Messrs. Hamilton and 

 Crosby, and from Mr. James Mackenzie ; but all too late for 

 insertion. 



We are not aware of any difference between the olive and the 

 green oxide of manganese, adverted to by our correspondent at 

 Cambridge. The sample enclosed in his letter is apparently a 

 pure protoxide of manganese, without any trace of iron ; we are, 

 however, surprised that it should have been obtained by the pro- 

 cess he describes. 



In reply to the numerous queries that are put to us respecting 

 new modes of tanning, new methods of making alcohol, steam- 

 guns, gas-engines, and the like, we beg to assure Veritas, An 

 Old Subscriber, A Constant Reader, and other inquisitive 

 persons, that although we form our own opinions we do not choose 

 to promulgate them at present. 



We cannot meddle with the complaints of " A Member of the 

 Athenseum." 



We are unable to offer even a plausible conjecture upon the 

 questions referred to us by a " Proprietor of the London Institu- 

 tion ;" nor can we give " Civis" any information, as we never even 

 heard the people's names before. 



As soon as the first twenty volumes of this Journal are completed, a 

 very copious generalindex of their contents will be published, which 

 will form a Supplementary Volume, and which, it is trusted, will be 

 found a valuable acquisition to the scientific reader. 



