TahUs of all the Frigorific Mixtures, &c. 177 



Its internal structure was uniform, and there was no ap- 

 pearance of a nucleus. It was composed of 

 Carbonate of lime - 90* 

 Animal matter - 10* 



100- 



7. The Rabbit. 



A calculus from the rabbit's bladder weighing four drachms, 

 was of a dark gray colour, and appeared as if composed of 

 several smaller c dculi. It consisted of 



Phosphate of lime - ^ 39* 

 Carbonate of lime ** 42* 

 Animal matter - lo> . 



100* 



[To be continued.] 



XXX. Table 1 ) exhibiting a collective View of all the Fri- 

 gorific Mixtures contained in Mr. Walker's Publica- 

 tion} 1808. 



To Mr. Tilloch. 



SIR, 



At will be found, on comparing the tables in the various 

 publications that have noticed the subject of artificial cold, 

 (Cavallo's Experimental Philosophy excepted,) with the fol- 

 lowing tables;,or with the tables in the Philosophical Trans- 

 actions, where these experiments originally appeared, that se- 

 veral errors, respecting the effects of the frigorific mixtures, 

 have happened.' An error of this kind in one instance, viz. 

 in the ninth mixture, of the first table, is no less than forty- 

 two degrees ; the result in that instance being — 21°, whereas 

 in the copied tables it is rendered 21°. 



This error seems to have arisen from the person who co- 

 pied the tables from the Philosophical Transactions, or 

 my publication, originally, having overlooked the minus cha- 

 racters expressed in Table I. altogether. 



Various other errors, likewise, will, on examination, be 

 detected, particularly in the first four mixtures of Table II. 



Desirous that these errors should be corrected in future 

 publications, I have taken the liberty of addressing this to you, 

 with a genuine copy. I am, sir, your obedient servant, 



Queen-Street, Oxford, ' Rd. WALKER, 



Nov. 13, 1808. 



Vol. 32. No. 126. Nov, 1808. M Table 



