TO OUR READERS AND CORRESPONDENTS. 



Mr. Vulliamy's paper on the Theory of the Dead Escapement, will 

 appear, with its illustrative plates, in our next Number. 



Mr. Johnstone's " Analytical Inquiries into the Nature of Nitrogen 

 and Ammonia," reached us too late for insertion ; the paper, therefore, 

 is disposed of according to his directions. 



We have received the " Edinburgh Critic ;" but his remarks appear 

 to us very irrelevant. 



A Member of the Apothecaries' Company is informed that we shall 

 probably give some account of the New Laboratory, and of the mode 

 of conducting business in it, in our next Number. 



A Correspondent, who writes to us upon the subject of Gas Works, 

 and signs himself *' Antu Alarmist ," is too voluminous, even for a 

 Quarterly Journal. 



We must decline all interference upon the subject of Mr. W. C.'s 

 Letter. 



Mr. Wrangham's paper shall appear in our October Number, pro- 

 vided he has no objection to its standing over till that time. 



We recommend a little more circumspection to our Correspondent, 

 who calls himself a " Practical Chemist." The Numbers in our Table 

 of Equivalents to which he alludes, are any thing but theoretical, and 

 are deduced, in all cases, from the experiments of others, or from ori- 

 ginal ones of our own. The number for gold with which he particu- 

 larly quarrels, happens to be deduced from the analysis of the insoluble 

 iodide, and as it closely corresponds with that derived fiom an analysis 

 of the triple chloride of gold and potassium by Berzelius, we had no 

 hesitation in adopting it. We cannot help its slight disagreement with 

 the experiments of MM. Pelletier, Oberkampf, ^c. Had we entered 

 into all our experimental details and data, we must have written a 

 volume. 



NEW WORKS PREPARING FOR PUBLICATION. 



Essays on Meteorology, by J. F. Daniell, Esq., F.R.S. 1 vol. 8vo. 

 A System of Mineralogy, by J. Mac Culloch, M.D., F.R.S. 

 A Manual of Pharmacy, by W. T. Brande, F.R.S. 1 vol. Svo. 



ERRATUM. 



In .Mr. Davies Gilbert's paper " On the Vibralious of Heavy Bodies," tlie first two lines 



ill page 97, should follow the Table, page 103. 



