THE TECHNOLOGIST. [June 1, 1865. 



526 SCIENTIFIC NOTES. 



inner circle of metropolitan railways will have a station within 200 

 yards of the Museum, to which there will probably be a covered passage 

 of communication. 



.Royal Polytechnic Institution. — We have much pleasure in 

 bearing testimony to the liberality of the directors of this institution, 

 where youth and age alike can be instructed and amused, in providing 

 such an intellectual entertainment as can there be obtained. To enu- 

 merate the varied attractions of this school of science would occupy too 

 much of our space, but we would especially invite attention to the new 

 optical illusion, called " Proteus ; or, We are here, but not here," the 

 joint inventors of which are Mr. J. H. Pepper, the indefatigable 

 manager of the institution, and Mr. Tobin, as being something truly 

 marvellous, surpassing all other efforts in the same direction. The 

 lecture entertainment in which the illusion is produced is illustrative 

 of Captain Richard K. Burton's pilgrimage to Mecca and Medinah, 

 besides some of the remarkable incidents in the life of Mahomet. An 

 exhibition of models and drawings of inventions calculated to promote 

 the saving of life in railway travelling is worthy of attention, the sub- 

 ject of safety in travelling over our iron roads occupying so much 

 attention at the present time. 



Use op New Substances. — The rate at which we have been dis- 

 covering new elements of late suggests some considerations respecting 

 the uses of new substances, which may have interest for readers to 

 whose minds it may not have occurred When the existence of iodine 

 was discovered in 1812, and that of bromide in 1826, who could have 

 conceived of those elements as likely ever to become of industrial 

 importance 1 At the dates of their discovery, no arts to which they 

 were capable of any application were as yet known (unless the medical 

 art may be regarded as an exception) ; but their discoverers have lived 

 to see grow up an entirely new art, to which these elements are essential, 

 and which was not long in attaining dimensions causing so great an 

 industrial demand for these new substances as to render the discovery 

 of new sources of them of \ery great economic importance. To meet 

 the demand for bromine, manufactories are about to be established on 

 the shores of the Dead Sea, the waters of which have been lately dis- 

 covered to be richer in bromides than any others known, while the 

 demand for iodine is such that he who shall first bring to this country a 

 lew hundred tons of the Chilian mineral recently discovered, may 

 realize, by only one cargo of it, a really considerable fortune. Is not 

 this of bromine and iodine a representative example, which ought to lead 

 us to regard the discovery of previously unknown substances as prophe- 

 sying the coming birth of new aits, for which these new substances are 

 the ordained materials ? It must surely be that everything in the world 

 exists for man, and that, while every element has one set of uses in the 

 economy of nature, it has another set also in the economy of art. — . 

 ' Mechanics' Magazine.' 



