IIG Reply io a Review in Brandes Journal of Science. 



Their mutual conversion is therefore verj' easy, for if we add to 

 Dr. Wollaston's number, its half, the sum is Sir H. Davy's; and 

 of course, if we subtract from the number of the latter, its third, 

 tlie remainder is Dr. Wollaston's number. There is one very 

 frequent variation in the weights of the primes among the best 

 writers, namely, doubling or halving the number. This differ- 

 ence is occasioned generally !)y an uncertainty about the first 

 term or proportion in which the body combines with oxygen ; 

 some chemists reckoning that a protoxide which others consider 

 a deutoxide. Thus Sir H. Davy gives 103 as the number re^ 

 presenting iron; from which, if we deduct ^ = 84 "3, the re- 

 mainder 687 is nearly double of 34-5, the number of Dr.Wol- 

 laston. But Mr. Porrett has very ingeniously shown that per^ 

 haps —- = \1'^, is to be preferred.* 



XVII. Dr. Graxvili-P-'s Reply to n Review in Professor 

 Braxde's Journal of Science. 



i. HE accompanving re])ly to an article contained in Mr.Brande's 

 Journal for January 1S21, on the subject of my work on Prussia 

 Acid, was sent to that gentleman, through the hands of a friend, 

 for insertion in his next num!)er. The result of this aj)plicauon 

 will be better understood by a perusal of the following laconic 

 correspondence. 



Saville-Row, Wcdnesilay Evening, Feb. 7- 

 " Dear Sir, — I send you a reply to the article contained in 

 vour last Number, purporting to be a review of my work on the 

 Prussic Acid. Dr. Hutchinson, a particular friend of mine, has 

 been kind eiiough to undertake to deliver it into your own hands, 

 to prevent mistakes; and he is instructed to request you will 

 have the goodness to name an hour in the evening of to-morrow, 

 when he may call for your decision, as to whether you will admit, 

 or not, the said reply for insertion in your next number for A|)ril. 

 In case of your declining to insert it — a circumstance which I 

 am far from contemplating — I have requested my friend to bring 

 back the manuscript, without any further comment. 



" I have tb.e honour to be, your humble servant, 

 *' IF. T. Bramle, Esq. F.R.S. &c. A. B. Granville." 



Two days afterwards, Mr. Brande returned me the manu- 

 script, with a short note, of which the following is the begiyning ; 



Thursday 



