Dr. Thomson — and his Answer. 337 



But as we conceive some instruction may be derived from an 

 exposure of his recent distortions of scientific truth, we think 

 it our bounden duty as Journalists, to bestow on the Doctor a 

 few parting admonitions, after which we shall leave him in the 

 quiet enjoyment of his self-importance. 



We had said in the Review, " We are at a loss to learn why 

 anew edition has come forth; it was not spontaneously called 

 for, and nothing but a decidedly superior work should have been 

 tendered to the public." The Doctor makes answer : " The 

 new Edition, I presume, was printed because the old had been 

 sold. I am not aware that booksellers proceed in any other 

 way *." Now the public should be informed, that during the 

 session immediately preceding the appearance of his sixth edi- 

 tion, his fifth of 1817, was currently rattled off at the Edinburgh 

 book auctions. 



To multiply editions in this way, by the aid of the hammer, 

 without the employment of the file, (limce labor,) may suit a book- 

 making factory, but is a great injustice to chemical students, and 

 ought therefore to be exposed and checked. " The assertion," 

 says he, " that the second volume is a repetition of the first, is so 

 palpably untrue, that the Reviewer must have been aware of its 

 inaccuracy when he made itt." Here we have his favourite 

 figure of speech, — perversion of an author's sense. The Reviewer 

 said, in discussing the merits of the second volume, " Before he 

 reaches the combustible acids, one hundred and thirty-three 

 pages are occupied with details, which, to a very great extent, 

 had been already given in the first volume. His unsalifiable 

 oxides are the two oxides of azote, the two of hydrogen, and 

 carbonic oxide, which occupy five sections. These are for the 

 most part repetitions of what he had given us before." Of these 

 book-making repetitions we shall now give some samples. 



*' If equal volumes of chlorine and hydrogen be put into a 

 glass tube, and exposed to the direct rays of the sun, an explo- 

 sion takes place. This curious fact was first observed by Gay 

 Lussac and Thenard. When two equal glass vessels, groimd so 

 as to fit each other, and filled, the one with dry chlorine, and 

 the other with hydrogen, are placed in contact, and exposed to 

 the light of day, but not to sunshine, the yellow colour gra- 

 dually disappears, and the mixture becomes colourless. If it 

 be now examined, it will be found converted into pure muriatic 

 acid gas, equal in bulk to the volume of the two gases before 

 combination. Hence it follows that this gas is a compound of 

 chlorine and hydrogen." " Muriatic acid, called hydrochloric 

 acid by Gay Lussac, is a gaseous body, invisible and elastic like 

 common air, and having a peculiar smell, and a very sour taste. 

 Water absorbs it with great avidity", so that it can be preserved 



* Answer, J) 244 t Answer, p. 345. 



