CHEMICAL SCIENCE. 211 



homogeneous, present similar deficiency in homogeneity with the 

 glass ; and he has the subject under further examination. 



ON THE DISTRIBUTION OF IODINE. 



A MEMOIR, it is well known, has been recently published in the 

 proceedings of the French Academy by M. Chatin, on the existence 

 of iodine in the atmosphere, in rain-water, soils, &c.* Mr. Me Adam, 

 of Edinburgh, in a letter to Prof. Jameson, published in the Philosoph- 

 ical Journal for July, states that he has endeavored with great care 

 to verity the results obtained by M. Chatin, but without success. As 

 the fixed alkalies and their carbonates were re-agents made use of by 

 M. Chatin, Mr. Me Adam is inclined to refer the iodine found, to 

 these bodies, Mr. Me Adam's success in detecting iodine in pearl 

 ashes leads to the belief that this substance will be found more gen- 

 erally distributed in the vegetable kingdom than it has hitherto been 

 supposed to be ; and this opinion is strengthened by the fact that it 

 has in several instances been detected in charcoal. 



RESEARCHES ON THE SULPHURETS WHICH ARE DECOMPOSABLE 



BY WATER. BY E. FREMY. 



THE object of this paper is to make known the production and 

 principal properties of a class of sulphurets hitherto little examined, 

 and the study of which is alike interesting to chemists and geologists, 

 from the light which it throws on the formation of mineral waters. 

 When we consider the action of water on the sulphurets, we find that 

 these compounds may be divided into three classes ; the first com- 

 prises the sulphurets of the alkalies and of the alkaline earths which 

 dissolve in water ; the second is formed of the insoluble sulphurets ; 

 the third consists of the sulphurets of boron, silicon, magnesium and 

 aluminum, which are decomposed by water ; these latter are scarcely 

 known, owing to their preparation having hitherto been accompanied 

 with great difficulties. In order to a thorough investigation of all the 

 questions which are connected with the decomposition of the sul- 

 phurets by water I first sought for a method by which they might be 

 easily prepared, which is as follows. It is well known that sulphur 

 exerts no action upon silica, boracic acid, magnesia and alumina. I 

 imagined it might be possible to replace the oxygen in these substances 

 by sulphur by "the intervention of a second affinity, as that of carbon 

 for oxygen. Such decompositions, produced by two affinities are not 

 rare in chemistry ; and in some yet unpublished experiments on the 

 fluorides, I had observed that the sulphuret of carbon completely 

 decomposed the fluoride of calcium mixed with silica, producing 

 sulphuret of calcium, I was therefore led to presume that the sulphuret 

 of carbon, acting by its two elements upon the preceding oxides, 

 would remove the oxygen by means of the carbon which it contains, 

 and would at the same time form sulphurets ; this supposition I found 



* See Annual of Scientific Discovery for 1851, p. 231. 

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