cxxvi GENERAL SUMMARY OF SCIENTIFIC AND 



which ai"e moulded and allowed to harden gradually as sili- 

 cate of lime is formed, by the decomposition of the alkaline 

 silicate produced by the action of the lime. The chemical 

 reactions involved in the production of the "Apoenite stone," 

 as the new product is called, are such that the whole of the 

 alkali is combined, and none left free to effloresce, as is the 

 case with the "Ransome stone;" hence no after-washing is' 

 needed. 



The part taken by American exhibitors in the great Indus- 

 trial Exposition just closed was altogether unworthy of the 

 commanding position which this country occupies in the esti- 

 mation of the world. The manufacturing industries of the 

 country were but meagrely represented ; but, despite the in- 

 completeness of the display, the American department of the 

 great fair, especially that portion of it relating to the me- 

 chanic arts, was the object of much interest and attraction 

 to visitors. The comments of the foreign engineering press 

 upon the originality of design, directness of conception, and 

 true mechanical adaptation displayed by the few exhibits 

 there exposed, as well as the recognition which they received 

 at the hands of the authorities, all render it manifest that, as 

 was the acknowledged fact at Paris in 1867, upon the field 

 of invention and machine construction America held the first 

 rank. While the meagreness of the American display at Vi- 

 enna may therefore be justly a matter of regret, we may feel 

 gratified at the praise bestowed ujDon that which was dis- 

 played. 



The movement for the Centennial Exhibition, to be held in 

 Philadelphia in 1876, has been vigorously pushed during the 

 year. The formal transfer of the grounds from the city of 

 Philadelphia to the Centennial Commission took place on the 

 4th of July, 1873, in the presence of an immense concourse, 

 and with imposing ceremonies. The design of the building 

 has likewise been decided uj^on, and the organization of state 

 societies to forward the interests of the important project has 

 been efi'ected. 



During the last year the demand for and supply of artifi- 

 cial Alizari7ie have very largely increased, though its manu- 

 facture can be said to have just foirly begun. The value of 

 madder has decreased to such an extent by the competition 

 with the manufactured article, that it has become a question 



