444 HENRY A. ROWLAND 



The correction for weighing in air was -835 / -00106. 

 The total term containing the correction is therefore -99878. 



log 86-324 =1-9361316 



log -99878 = 1-9994698 



1-9356014 



log 8-7469 = -9418542 



log const, factor = -9937472 = log 9-85706. 



Hence the work per kilogramme is 9-85706 S~Wn in gravitation 

 measure, the term 2'Wn being used to denote the sum of products 

 similar to Wn as obtained by simultaneous readings of torsion circle 

 and records on chronograph sheet. 



Zero of torsion wheel, 79-3 mm. 



Value of 1 mm. on torsion wheel -0118 kil. 



The following were the records of time on the chronograph sheet : 



Time observed. Revolutions of Chronograph. Time calculated. 



15 8-74 15-2 



20 25-32 20-1 



25 42-10 25-0 



30 59-05 30-0 



35 76-00 35-0 



40 93-03 40-0 



45 109-97 45-0 



50 126-92 50-0 



55 144.14 55-0 



The times were calculated by the formula 



Time = -294 X Revolutions + 12-66, 



which assumes that the engine moves with uniform velocity. As the 

 principal error in using an incorrect interpolation formula comes from 

 the calculation of the radiation, and as this formula is correct within 

 a few seconds for all the higher temperatures, we can use it in the cal- 

 culation of the times. 



The records of the transits of the mercury over the divisions of the 

 thermometer were nearly always made for each division, but it is use- 

 less to calculate for each. I usually select the even centimeters, and 

 take the mean of the records for several divisions on each side. 



While the mercury was rising 1 cm. on No. 6163, there would be 



