Mr. R. Phillips on the Purity of Sulphate of Quina. ill 



results differing a little from those of other chemists, who pro- 

 bably did not take the necessary pains to obtain this acid in a 



perfectly pure state. 



In conclusion, I wish to observe, that I purposely abstain 

 at present from making any further observations on the pre- 

 ceding results than those already given. I do this for several 

 reasons : in the first place, such observations will appear with 

 greater effect, when the whole of the facts in my possession 

 are laid before the public ; and secondly, I consider that data 

 which lead to such important conclusions as these appear to 

 do, cannot be too firmly established ; I therefore, in the mean 

 time, earnestly invite chemists in general to repeat them, and 

 thus either to confirm them, or point out their errors ; and 

 for the sake of those who may be inclined to take this trouble, 

 I shall close this part of the subject with the following re- 

 marks: 1. The multiples of hydrogen, carbon, and oxygen, 

 are assumed in the preceding calculations as 1 : 6 : 8. 2. The 

 results given are, on all essential points, the means of many 

 experiments, the differences among which are either inappre- 

 ciable, or at most vary from *01 to *03 of a cubic inch in 

 from 5 to 8 cubic inches of carbonic acid or oxygen gas ; the 

 greatest differences in general being, for obvious reasons, found 

 among merorganized bodies ; and hence the analyses of these 

 are usually stated to the first decimal figure only. 3. As rules 

 to be observed, I would say, that a single result should never 

 be registered, nor a single calculation made, till the operator 

 has made himself complete master of his apparatus, and care- 

 fully studied the nature of the substance to be analysed ; for 

 different substances often require very different management : 

 that two or three results should never be relied on ; the mi- 

 nute quantities here sought can be only obtained, like those 

 of astronomy, by repeated observations : and lastly, the ut- 

 most care should be taken that the substances operated on be 

 pure, a point of greater importance, and frequently of more 

 difficult accomplishment than any other, and one that has 

 caused me more trouble than all the rest put together. 



XVIII. On the Means of ascertaining the Purity of Sulphate 

 of Quina. By R. Phillips, F.R.S. L. % E. $c. 



HPHE great demand which has arisen for this important me- 

 A dicine, and the high price at which it is necessarily sold, 

 have excited some, who are careless as to the means by which 

 they acquire gain, to sophisticate it in a vast number of ways,- 

 and by every means which talent misapplied could suggest. . 



Having 



