Dr. Thornton's Second Letter to Mr. Arthur Aikin. 141 



mer, and the porosity so visible in the last was considerably 

 diminished. A portion of the carbonaceous matter remained 

 untaken up which weighed 3-4ths of a^grain, so that in this 

 experiment 4£ grains of carbon had disappeared, and united 

 with the silex. This is equal to 8^- per cent., or 1-1 2th 

 part, the weight of the silex. 



It will not therefore appear rash to conclude, from these 

 experiments, that carbon in high temperatures unites with 

 siliceous matter in the same manner as indicated by the.ex- 

 periments with clay, and that its colour and appearance are 

 totally changed by the union. 



The conclusions to be drawn from these experiments, and 

 facts in general, so far as they regard the manufacture of 

 iron, will present themselves with more force of reasoning 

 connected with the analysis of artificial and natural iron ores, 

 containing solely or in excess a particular earth of the be- 

 fore-mentioned varieties. 



The present may be concluded with one general remark, 

 that the carbon does not appear to enter siliceous matter by 

 cementation, as was evident in exposing the two siliceous 

 crystals No. VI. In the experiments with clay, not only a 

 mass of Cornwall clay was pervaded by the carbon, but 

 many of the crucibles used in all these experiments were 

 frequently penetrated a considerable portion of their thick- 

 ness. 



^[To be continued.] 



XXV. Dr. Thornton's Second Letter to Mr. Arthur 

 Aikin. 



July io, 1804.. 

 SIR, No. 1, Hind -street, Manchester-square. 



JL was almost morally sure that you could never have allowed 

 such gross ignorance and abuse to have passed in your An- 

 nual Review, had you " been aware of it," as have been ex- 

 hibited in the "critique" on my work. Certainly you must 

 have been planet-struck, when you read, probably, for the 

 first time, in the letter I had the honour to address you, that, 

 in your review, it was asserted that the satellite of Venus 

 had not been mentioned in any work on astronomv, and 

 that this before unheard of moon was of ?ny invention ; 

 which seemed to afford your reviewer an opportunity of 

 fpewing out a torrent of personal abuse against me. Such 

 conduct could not fail to astonish one, who was in the ha- 

 bit of esteeming you before as a scholar and a gentleman, 

 a character adopted from your learned father, and which I 



should 



