52 



Mr. Herapath on True Temperature, and the [Ju ly, 



ISO 



third column. It is computed from the formula g — x (v — 1000) 



•4- 32, in which v denotes the volume of the gas, 1000 being its 

 volume at 32° of Fahrenheit. In these numbers I have carried 

 the calculation to tenths of a degree only, which is as near as 

 we can generally depend on experiments, or, perhaps, nearer. I 

 have likewise, in the first 800 degrees, thought it sufficient to 

 compute the Fahrenheit temperature to every hundredth of our 

 decrees. From hence to 900, or 100 below the zero of Fahren- 

 heit, I have calculated them to every 10th degree, thence to a few 

 decrees above the boiling of mercury to every degree ; for about 

 90 degrees afterwards to every 10th degree ; and afterwards to 

 every 100th. 



Though I have thought it sufficient to carry the comparison 

 between the true temperature and Fahrenheit's indications to 

 lOths of a degree only, yet in order that those who choose may 

 cany it to hundredths, 1 have computed it at every 10th degree 

 to hundredths, and placed the difference of the 10 degrees late- 

 rally between the two 10 degrees. 



By the help of these differences, and Table I. the true temper- 

 ature to lOths of a degree, may be found, corresponding to any 

 temperature of Fahrenheit within the limits calculated, and vice 

 versa ; and by the help of the numbers under the titles of " Elas- 

 ticity or Volume of Gas," and Table II. the Fahrenheit tempera- 

 ture corresponding to any true temperature may be taken out to 

 any degree of accuracy, or the contrary. 



TABLE I. 



TABLE II. 



