Mr Blackadder on the changes which take pluce, <Sfc. 47 



some of the bones, marks may be traced which, on applying 

 one to the other, appear exactly to fit the form of the canine 

 teeth of the hyaenas that occur in the cave." 



I have seen bones from the cave at Kirkdale, in the posses- 

 sion of Professor Sedgwick, and some also in the Institution 

 at Bristol ; and my conclusion was, that their fracture pro- 

 ceeded from the causes which Dr Buckland has assierned. 



Another circumstance (and which Dr Knox has omitted to 

 remark upon) tends greatly to confirm me in that conclusion ; 

 and that is, the presence of so considerable a quantity of Al- 

 bum Grcecum. — this circumstance deserves particular attention. 

 Again, at page 120, Dr Buckland says, the state of the bones 

 at Bauman's Hohle " is totally different from that of the 

 splinters in the den at Kirkdale, which latter are as obviously 

 the effects of fracture by the hyaenas teeth, as the former are 

 of a violently crashing blow, imparted by a heavy mass of 

 stone." 



Art. VIII. — Observations on the changes which take place on 

 Mercurial Thermometers. By H. H. Blackaddek, Esq. 

 F. R. S. E. Communicated by the Author. 



It has been remarked, by various observers, that the most ac- 

 curately constructed mercurial thermometers are liable, in the 

 course of long use, to become inaccurate ; and, in such cases, 

 it is a lowering of the original height of the mercury that has 

 been observed to take place. This change, to which mercurial 

 thermometers are subject, has been attributed to a permanent- 

 ly increased capacity of the bulb, produced insensibly during 

 the successive heatings and coolings to which it has been ex- 

 posed. This explanation, however, appears unsatisfactory — 

 for the change in question has been observed to take place in 

 instruments, in the construction of which great care had been 

 taken to extract the air from that part of the tube that is not 

 filled with mercury. If the glass bulb were to suffer any per- 

 manent change in such instruments, during the frequent but 

 moderate alternations of temperature to which they are ex- 

 posed, we would have reason to expect that its capacity would 



