330 Mr, Brooke's Repli/ to Dr. Brewster. [Jf pTf 



Article III. 



On sofne Observations by Dr. Brewster in the fifth. Number of 

 the Journal of Sciencey concerning the Crystalline Forms of 

 Sulphate of Potash. By H. J. Brooke, FHS. &c. 



(To the Editors of the Annals of Philosophy.) 



GENTLEMEN, Oct. 15, 1995. 



It is only within the last week that I have seen an article 

 relating to myself in the fifth Number of Dr. Brewster's Journal 

 of Science, p. 147, containing insinuations and assertions which 

 are wholly unsupported by fact. 



The article in question is one of those which Dr. Brewster 

 occasionally inserts under the title of " Decisions on disputed 

 Inventions and Discoveries." 



On the general question of original discovery, we may borrow 

 from Dr. Brewster's own case an illustration of what ought or 

 ought not to be regarded as such. 



Dr. B. either did or did not pilfer the kaleidoscope from 

 Bradley. If he did not ; if, during the industrious and extensive 

 researches to which, as the editor of an Encyclopaedia, we may 

 conceive him to have been led, he did not happen to meet with 

 Bradley's volume before he discovered the principle of the instru- 

 ment himself; and if on this ground he claims the merit of being 

 an original discoverer of a principle which was already knoion; 

 it would in him be no more than an exercise of common candour 

 to concede to other second discoverers an equal claim to origina- 

 lity, except indeed in those instances in which there is strong 

 moral presumption, if not direct evidence of plagiarism. 



The article I have alluded to is the foUowins: : — 



o 



*' Our mineralogical readers are no doubt aware of the bypjo-amidal form in which 

 sulphate of potash often crystallises. Count Bournon considered this the primitive form 

 of Uie salt. In a paper in the Annals of Philosophy^ Mr. Brooke has described this 

 form of the salt, and shows that it is a composite form, consisting of rhomboidal prisms 

 combined in the manner tcldch he has represented in a diagram. 



" This composite form had been discovered long before by the agency of polarised light, 

 and the combination distinctly described in the first paper of No. I. of the Edinburgh 

 Philosophical Journal. 



** j4s Mr. Brooke has made no reference whatever to that paper, it might have been 

 presumed that he. had not read it. But we find that he has actually read it and quoted it 

 in his lucubrations on the structure of apophyllite, with which he has favoured the 

 public ; and which have already shared the same fate as his speculations on the primitive 

 form of the sulphate -tri-carbonate of lead." 



Now the insinuation which this article is intended to convey, 

 standing as it does among the notices of " disputed discoveries,'' 

 is, that I have assumed the credit of discovering something 

 which was already known, and had been previously discovered 

 by Dr. Brewster. 



