14 On the Propagation of Heat by Conduction, fyc. [Nov. 17, 



Average effects of 0°*1 C. through 7*5 millims. of sheep's skull aud 

 3 millims. of sheep's scalp, taken together. 



At the end of 2 minutes. . 

 When the permanent ther- 

 mal state was reached. . 



Degrees of 

 galvanometer. 



Thermometric 

 values. 



Percentages of 

 heat transmitted. 



11 -409° 

 86 -033 



-007692° C. 

 -058006 



7 -692 per cent. 

 58 '006 



Lastly, we will calculate what effect a change of temperature of 

 0°'l C, at one point of the cerebral surface, would have on a point of 

 the outer surface of the scalp situated over another point of brain 

 surface distant 7*5 millims. from the point where the change of tem- 

 perature occurs. We have, in this inquiry, first, to take the alteration 

 of temperature produced by transmission through 7'5 millims. of brain- 

 tissue (pages 12 and 13), and then to calculate how much of this 

 heat would find its way through the 7'5 millims. of skull and the 

 3 millims. of scalp (see page 13). 



Average effects of o, l C. on the outer surface of the head after first 

 passing through 7*5 millims. of brain-tissue. 



At the end of 2 minutes. . 

 "When the permanent ther- 

 mal state was reached. . 



Degrees of 

 galvanometer. 



Thermometric 

 values. 



Percentages of 

 heat transmitted. 



4-873° 

 65 563 



0-003286° C. 

 -044202 



3 '286 per cent. 

 44-202 



If we compare the above figures with those previously given as the 

 results of the direct transmission from the point of the brain-tissue, 

 the temperature of which is altered o, l C.,* it is easy enough to see 

 that, with the apparatus we are employing, the temperature of a point 

 of the outer surface distant 7*5 millims. from a point lying directly 

 over the focus of change would present differences very easy of 

 detection. 



The following figures show the excess of the direct over the indirect 

 transmission. 



* See page 13. 



