Meteorological Observations for June 1830. 157 



It is plain that Lieut. Schmidt mistakes the meaning of the word 

 effect, as used by Mr. Wright. The fulminating quicksilver makes 

 a louder report than the ordinary fulminating powder, but will not 

 fire the magazine at so great a distance. Its fire is rapid, but not 

 elastkj or expansive, as it quickly condenses, and returns to the state 

 of mercury : it is, however, certain, and presents no difficulties 

 whatever. 



The most extraordinary part of the statement is, that the fulmi- 

 nating quicksilver is more corrosive than the oxymuriate prepara- 

 tion ! With what difficulty do we sometimes arrive at the most 

 simple truths ! Nothing can be more gratuitous and false than the 

 above conclusion. Mr. Forsyth of England expended, it is said, a 

 hundred thousand pounds in his attempts to establish the use of the 

 percussion magazine lock, in which he failed altogether, from the 

 corrosive effects of the powder ; the whole 14 years of his patent were 

 devoted to this point. As soon as this period had terminated, Mr. 

 Wright introduced the fulminating mercury, since which there has 

 been no complaint whatever of the corrosion of locks and barrels, 

 excepting from the use of imported caps charged with the old ma- 

 terials. 



The cement used is a point of much importance: gum benjamin 

 and gum arabic have been principally employed j the first is always 

 soft, the latter attracts moisture ; neither of them answers well. The 

 French, to obviate the defects of both these, sought the remedy by 

 enlarging the caps at the bottom, so that when the powder is intro- 

 duced and dry, it is, as it were, dove-tailed in, and a smaller quantity 

 of either of the foregoing ingredients will retain it. This lessened, 

 but did not remove the evil. 



In America, the percussion gun has, in consequence of the man- 

 ner in which the caps have been made here, been more generally em- 

 ployed than in England, although the guns themselves are the manu- 

 facture of that country. We have, it is true, ran counter to the rules 

 established by the German officer and professors ; for, although we 

 may be less scientific in these matters, we know enough of the amuse- 

 ments of the field, to derive from our experience that information 

 which suits us better than the most learned theories, and we even 

 venture to adopt the suggestions of the former, although opposed by 

 the deductions from the latter. 



Should you think proper, sir, to give this a place in your Journal, 

 I shall again request a small place for some future observations, con- 

 taining the practical results of my own experience, as it may interest 

 a certain portion of your readers. Yours, &c. 



Philadelphia, March 20 , 1829. Joshua Shaw. 



[We have not met with any further communication on the subject 

 in the Journal of the Franklin Institute. — Edit. Phil. Mag.] 



METEOROLOGICAL OBSERVATIONS FOR JUNE 1830. 



Gosport: — Numerical Results for the Month. 

 Barom. Max. 30-15. June 2. Wind W.— Min. 29-38. June 22. Wind N.E. 

 Range of the mercury 0-77- 



Mean 



