132 SUPPOSED FORTIFICATIONS OF 



the two kinds of air may be de-composed, and a highly de- 

 phlogisticated nitrous acid, as mine always was, procured. — 

 This, being formed, will, of course attach itself to any snow 

 or hail that may be forming in the same region at the same 

 time, and by this means be brought down to the earth ; con- 

 firming, in tbis unexpected manner, tbe vulgar opinion of 

 nitre being contained in snow. Wishing that a fact of so ex- 

 traordinary a nature, and which lias probably more import- 

 ant consequences that I can foresee, may be farther investi- 

 gated by your presenting this communication to the Philoso- 

 phical Society. 



I am, Dear Sir, 



Your's sincerely, &c. 



JOSEPH PRIESTLEY. 



Northumberland, Nov. 21st, 1803. 



Dr. C. Wistar, one of the) 

 V. P. of the A. P. S.) 



No. XXVI. 



A Letter on the supposed Fortifications of the Western Country t from 

 Bishop Madison of Virginia to Dr. Barton. 



Read Dec. 16th, 1803. 

 DEAR SIR, 



HAVING lately visited that beautiful river, the Kanha- 

 wa, and a considerable part of the countrv, within its neigh- 

 bourhood, an opportunity was afforded of examining with at- 

 tention some of those remarkable phenomena, which there 

 present themselves, and which have been so much the subject 

 of conversation, and of literary discussion. r l o remove error 

 of whatever kind, is, in effect, to promote the prugress of 

 intelligence; with this view, I will endeavour to prove to you, 

 that my journey has enabled me to strike one, at least, from 



