1824.] 



Mr. J. H. Patten on a new Air Pump. 



255 



Nitric Acid. 



Temperature. Volume. Log. of 



50° 100000 12589-2 



80 —1530 12633-6 



110 —3196 12682-2 



140 —5132 12738-9 



Diff. of numbers. 



44-4 

 48-6 

 46-7 



Temperature. 



50° . . . 

 70 ... 

 90 ... 



Wafer. 



Volume. Log. of 



100023 12590-0 



197 12594-0 



-694 



12669-3 



Diff. of numbers. 



.. 4-9 

 .. 4-4 



Alcohol. 



Temperature. 



Volume. 



Log. of 



Diff. of numbers. 



40° 100539 12604-8 



60 



80 



100 



—1688 12638-2 



—2890 12673-3 



—4162 12710-4 



33-4 

 35-1 

 37-1 



On account of the great expansion of alcohol, and the lowness 

 of its point of ebullition, the expansion arising from the arithme- 

 tical series, which has to be multiplied into the geometric, is 

 very perceptible ; in all the others, the inequality of the differ- 

 ences in the fourth column is less than the inevitable errors of 

 observation. 



To show the comparative expansions, the volumes of the 

 liquids should not be equal at a given temperature, but should be 

 the volumes of weights which are proportional to the atomic 

 weights ; then the above numbers will enable us to determine 

 the relative quantities of caloric contained in the above volumes. 



These points will form the subject of a separate communica- 

 tion. I am, &c. J. B. Emmett. 



Article VI. 



Account of a new Air Pump. In a Letter to the Editor from 

 Mr. Joseph H. Patten* (With a Plate.) 



I inclose for your inspection the draught of a pneumatic 

 pump, which, 1 think, will, in a considerable measure, obviate 

 the defects of those in common use. The construction is so 

 simple that it will require but a small share of skill or ingenuity 

 to put it together, and it will be less liable to get out of repair 

 than the pumps now in use. The valves which in other machines 



From the American Journal of Science. 



