184 Dr. J. S. Lombard. On the Propagation of 



was 28*4 seconds. In 53*333 per cent, of the cases it was 23 seconds ; 

 in 26' 667 per cent, it was 38 seconds ; and in the remaining 20 per 

 cent, it was 30 seconds. 



If the results of the different experiments are calculated for 0°'l C. 

 difference of temperature, on the basis that the time required would 

 be inversely proportional to the degree of difference of temperature, 

 the average time is found to be 37'3 seconds, the maximum and the 

 minimum being respectively 55*86 and 26*29 seconds. The average 

 rate of the thermal transmission is, therefore, 1 millim. per 4*9733 

 seconds, the maximum and the minimum times being, respectively, 

 7*448 and 3*5053 seconds. 



(5.) Degree of change of temperature produced at certain measured 

 intervals of time. 



We will examine the changes produced at the end of 1 minute and 

 15 seconds, 2 minutes, 4 minutes, and 6 minutes, respectively, measured 

 from the moment when the bone touched the water. We will take 

 simply the averages and extremes of the changes due to the differences 

 of temperature given under the preceding heading, having first, how- 

 ever, reduced all the results to values representing the effects of 0°'l C. 

 difference. Table I gives these averages and extremes in both galva- 

 nometric and thermometric figures. The galvanometric deflections, 

 it will be seen, indicate the steps towards equalisation of the tem- 

 peratures of the two surfaces of the bone at the several periods: 

 thus, as 0°*1 C. is equal to 148 316° of the galvanometer,* and as 

 0°'l C. represents the difference of temperature between these two 

 surfaces at the start, the steps towards equalisation are measured by 

 the approximation of the figures of the galvanometric degrees to 148*316. 



Table I. — Effects of 0°*1 C. difference of temperature through 7*5 

 millims. of sheep's skull. 1° of galvanometer is equal to 0°*0006742 

 C. ; and o, l C. is equal to 148°*316 of galvanometer. 



Time from the 

 moment of 



contact of bone 

 and water. 



Averages. 



Maxima. 



Minima. 



Degrees 

 of 



galvano- 

 meter. 



Thermo- 

 metric 

 values. 



Degrees 

 of 



galvano- 

 meter. 



Thermo- 

 metric 

 values. 



Degrees 

 of 



galvano- 

 meter. 



Thermo- 

 metric 

 values. 



At the end of — 



1 min. 15 sec. 



2 „ „ 

 4 „ „ 

 6 „ „ 



23-86-i 

 51-170 

 SS-804 

 116-476 



0-01609° C. 

 003652 

 0-059S7 

 0-07853 



34-916° 

 74-720 

 115485 

 135-384 



0-02354° C. 

 0-05038 

 0-07786 

 0-09127 



13-058° 

 30-470 

 40-000 

 68-504 



0-00845° C. 

 0-02054 

 0-02696 

 0-04618 



* 1° C. is equal to 14S3 0- 16 of the galvanometer ; hence 1° of the galvanometer is 

 equal to 0°-0006742 C. 



