210 On the Preparation of Indian Ink, 



standard of comparison will be one which does not diffrr 

 exceedingly from that of which we have hitherto had some 

 indefinite idea. 



§ 30. It nuipt be recollected, however, thct this circum- 

 stance, though it may render these tables less convenient 

 for practical use, by no means lessens their value, consi- 

 dered as a register of experimental results. It is true, they 

 will not give an answer with respect to equivalent quanti- 

 ties of liquors of all strengths by mere inspection ; but we 

 can deduce from them, by calculation, any mformation 

 respecting this subject which we may be desirous of ob- 

 taining. 



The modes of doing this will, of course, easily occur to 

 tlie mathematical reader : we shall, however, make no apo- 

 logv for presenting the public with rules and examples for 

 finding from these tables a solution of almost every question 

 which can occur in the course of practice, on the supposi- 

 tion that proof spirit is of the specific gravity of 920 at 60°, 

 and that the mode of comparison emploved is that recom- 

 mended in § 20 ; and which, mutatis mutandis, will also be 

 applicable to any other standard which may be adopted. 

 They have been of some advantage to the authors in the 

 course of their trade, and they will probably not be useless 

 to society. 



[To be continued. 3 



XXXV. On the Preparation of India ti Ink ; presenting an 

 easy and expeditious Method of' providimr a Substitute 

 possessing all its valuable Properties, By THO^tAS Gill, 

 Esq. 



To Mr. Tilloch. 



y SIR, Londcin, Nov. 15, igoj. 



In a former communication * I mentioned that the Chi- 

 nese mixed their water colours up with parchment size: I 

 am now able to furnish you with a coi^firmation of thSt 

 fact, in a discovery I made a few days since, of a composi- 

 tion possessing all l!ie valuable properties of Indian ink, 

 which is as foQows : 



Boil parchment slips, or cuttings of glove leather, in 

 water until it forms a size, which on being suffered to 



Sec our last volume, p. 171. 

 3 cool 



