PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 467 



American Institute Polytechnic Association, ^ 



June Ith^ 1866, ^ 



Prof, S. D. Tillman in the chair ; Mr. T. D, Stetson, Secretary, 



Improved Steam H.vmmee. 



Dr. EowcH exliibited Shaw &, Justice's steam hammer. Ait 

 upright fnmie is fitted t'O a trasisvei'se stiaft at the top, oh Avhick 

 is a crank-wlieel , to thu crank is attached a connecting rod. This 

 5'od is attached to a spring and w<5rks the haaimer in a guide-brace, 

 •The harajMcr, in its reciprocating motion, strikes with a force pro- 

 portioeed to its velocity. When the revolutions of the driving 

 wheel are iucreesed mpidly the eiSciency of the machine is very 

 ^reat — a hundred pound hammer being ca,|5able of drawi«]g a four 

 anch bar dowii to any desired thickness at one heaL It strikes 

 with ahnost iri'esistibie force, and is eqiial in round numbcirs to a 

 blow of 20,0OG pounds weight. 



Improved M<?ui:h-piece for iNHAiiiNG Gas, 

 Dr. White exhibited and exphiined his improvement in the 

 Knouth-pieoe of bags for inhaling nitrous oxide gas, by which the 

 pure gas is inhaled at every respiration. The gas being once 

 respired is not allowed to mix with the breath and again enter 

 the bag, but at every exhalation a valve opens and the expired 

 breath passes into the air. The corpuscles of the blood are con- 

 •cave, biEt wlaen acted u.pon by alcohol, ether or chloroform, they 

 become convex. Nitrous oxide changes dark blood to sred. Blood 

 acted on by alcohol is of a brick color, and no amount of agitatioia 

 will restore it to its original appeara«08. But after the use of 

 aiitrous oxide, however, we find that the blood returns to its origi- 

 nal color. Dr, W. preferred to give the gas when there was no 

 catarrh present, through the Kose, as in that case the masseter 

 muscfe is net contracted ^v rigid, but by breathing throngh the 

 mouth this muscle will become so fixed that the operation of teeth- 

 drawing will be verj'' difficult. When a i>erson, before taking the 

 ,gas, was crying, after the effects of tiie gas have passed off he 

 will begin to cry exactly at the jwint where he left off. He would 

 not say that breathing the gas was not dangeix)iis, as deaths have 

 occurred from it', but if a little caution is exercised no fears need 

 be entertained. He had used it over a year with no unpleasant 

 result. If air is mixed with the gas the patient Avill know every- 

 thing that takes place. He i^ept Dr, Chamberlaiu iu this coiidi- 



