g 25 Extracl of a Letter from Dr. MitchilL 



further from each other. The blow-pipes b,i, alfo tartl at 



k,l, in the tunes fig, to enable the operator to alter the 

 direction of the dreams, and make them fall on the char- 

 coal ?n, at anv angle he pleafes. The double blow-pipe juft 

 defcribed was that employed in all the experiments, from thy 



8th to the 31ft inclufive. 



VII. Extraa bf a Letter from Dr. Sam. L. Mitchill, 

 Yrofrffbrof Chemijby in Columbia College, to Mr. Tilloch. 



SIR, New-York, Dec. 3, 1 Soo, 



- • ' • CONSIDERING all things, I really 



truft that the weftern world is doing its part in the philofo- 

 phical work of the day. We have great and excellent oppor- 

 tunities of obferving phaenomena here, and fome among us 

 arc diligent to let no opportunity be loft. The following 

 points we think fully eftabliffted : 



1. There is proof as pointed as it needs to be, that the 

 fickly fcafons which afflict our cities are accompanied with, 

 and occafioned bv, noxious exhalations, locally produced 

 either on board fea-veflels, or in (lores, cellars, dwelling- 

 houfes, and fmks, in our towns. 



2. When exifting in mips, thefc noxious productions arc 

 not received on board in the ports of the Well Indies, oc 

 other places beyond fea, as is vulgarly believed, but uni- 

 verfally are produced within the fides of the veflel itfclf, from 

 nallinefs and corruption there. 



3. Not only are the exhalations from our corrupting ff}:^ 

 beef, and hides, and from our abominable privy-pits, very- 

 injurious to health, and deft motive of life, but thefe very 

 vapours are fo acid as to be fmelled and tailed by the re- 

 packers of provifions. 



4. In the alimentary canal of fuch perfons as feed upon 



beef and fifli, and, g erally lpeaking, of lean animal fub- 



flance, there is formed fimilar acid, whofe prefence has 



been detected, and of a iu igth fnfficient to curdle milk, 



to excoriate the fundament, a»td to effervefce with carbonats 



of alkaline falts. 



5. The 



