256 Dr. Schoenbein's Conjectures on the 



not accord with the grand total, nor can I, as I have already 

 said, check them. I think however that there is enough to 

 prove that on the 10th of August at least there has been 

 nothing to support the idea of a common focus. I also must 

 add, that on the following night there were only 3 per hour 

 less in number." 



XXXV. Conjectures on the Cause of the peculiar Condition 

 of Iron. By Dr. Sch(enbein.* 



CEVERAL attempts have already been made to explain 

 ^ the pecuhar condition of iron. Dr. Faraday's hypothesis 

 upon that subject is certainly the most ingenious and most 

 plausible of all the theories as yet brought forward, but 

 there are some facts pointed out by me elsewhere, which do 

 not well agree with the views of that distinguished philosopher. 

 As the matter alluded to is of some importance with respect 

 to electrical science, and all the theories hitherto announced 

 upon the cause of the anomalous relations of the iron having 

 failed, I may, perhaps, be allowed to suggest some ideas re- 

 garding the delicate point in question. But before doing it 

 I must not omit to say, that I do not lay much stress upon 

 my conjectures, and that I have only ventured to make them 

 public, because I hope they will engage some philosopher 

 more able than myself to take up the subject, and clear up by 

 new investigations the darkness which still invests the cause 

 of the inactivity of iron. 



Chemistry in our days accounts for the difference of qua- 

 lities exhibited by what are called " isomeric bodies" by 

 asserting that the same number of particles of the same ele- 

 ments are capable of grouping themselves in different ways. 

 Now if heterogeneous atoms be capable of combining in va- 

 rious manners, is it not possible that homogeneous ones may 

 do the same, and in such a way as to give rise to substances 

 essentially distinct from each other not only with regard to 

 their physical, but also as to their chemical properties ? Sul- 

 phur, selenium, phosphorus, and carbon prove indeed that 

 simple substances are capable of assuming states almost as 

 different from each other as any two isomeric bodies are in 

 qualities. It is true, the difference of properties which we 

 sometimes observe in the same element is generally referable 

 lo a modification of the cohesive attraction of its molecules 

 brought about by the agency of heat; but I am almost sure, 



• Communicated by Mr. Faraday, to whom it had been addressed by 

 the Author. 



