1S14.] Astronomical and Magnetical Observations. 139 



July '.*. — Tlic needles vibrated 6' 30" : and the following day was 

 also very rainy. 



„ . r „ (Belween noon of tlie list June) „„,, . , 

 Ram fallen i ,. e . , , . } 2041 inches. 



I Between noon of the 1st July ^ 



Article XIII. 



On the Extrication of Caloric during the Coagulation of the 

 Blood. By John Gordon, M.D. F.R.S.E. and Lecturer on 

 Anatomy and Physiology, Edinburgh. 



(To Dr. Thomson.) 



DEAR SIR, Edinburgh, July 1, 1S14. 



My friend Dr. John Davy, in his interesting thesis (Quaedam de 

 Sanguine Complectens) printed here last month, has alluded to an 

 experiment of mine, relating to the extrication of caloric during 

 the coagulation of the blood, which 1 have been accustomed to 

 mention in my anatomical and physiological lectures for three years 

 back. In the lectures on physiology which 1 delivered during the 

 three summer months of last year, the limited period of the course 

 did not permit me to dwell so long on that, nor on many other 

 subjects, as 1 could have wished. To this, 1 doubt not, it is to be 

 attributed, that the experiment referred to has been in some degree 

 misapprehended by Dr. Davy ; and if by him, who honoured me 

 with the most flattering attention dining the whole of that course, I 

 fear al<o by many other of my pupils. 



The following, however, are the notes relating to this subject, 

 from which I then read : — 



" As it i- a fact established in chemistry that the conversion of a 



fluid into a solid is always accompanied with an extrication of 



lie, one could have little doubt, even if the fact were not made 



evident by experiment, that caloric is extricated during the coagu- 



ii of the blood. 



'• Pourcn y bad stated it, as the result of experiments made by 



at »bc l J ai is Lyceum, in 1 7-J0> that during the coagulation of 



bullo \.'- blood as much caloric was given out as raised the thermo- 



rleaumur's, I presume,) five degrees. (Ann. de Chimic, 



t. .ii. p. 147-) 



" Ian more authority seems to have been attached by physiolo- 

 gies to 1 Ik following experiment of Mr. John Hunter. Mr. 

 Hunter having suspended a healthy turtle by the hind legs, cutoff 

 it- head, and caught the blood in a bason. The blood while flowing 

 . and when collected was 66°, but fell to 65° while coagu- 

 lating, which it did rery slowly. It remained at 65°, and when 

 ulated was still 65°, From this, and similar experiments, Mr. 



