316 French National Institute. 



shown what arc the descriptions of manufactories which are 

 injurious to the hcahh of the surrounding inhabitants ; and 

 measures have been suggested for removing such as are 

 nuisances, without compromising the interests of the pro- 

 prietors. 



A report has been made to the Institute on a memoir by 

 M. Tarrv, relative to the composition of writing ink. The 

 author has succeeded in making an ink which cannot be 

 destroved by the acids or alkalies, and which has only the 

 slight inconvenience of allowing its colouring matter to be 

 deposited rather too easily. ** 1 he discovery of M. Tarry," 

 says the reporter, " promises a great benefit to society ; 

 viz. the introduction of an ink, which, not being susceptible 

 of being obliterated by the chemical agents at present 

 known, will put an end to the falsification of writings, 

 which is but too common.'* 



Another, on the artificial turquoises of M. de Sauviac, 

 gives reason to hope that art will shortly rival nature in 

 these productions, and furnish a new source ot riches. 



A committee has been busily employed in examining a 

 process of the late M. Bachelier, for the composition of a 

 preservative plaster of Paris. Houses built of stone are 

 (]uickly covered with an earthy coating, of a dirty gray 

 colour ; and this first change is the cause of the deteriora- 

 tion which thev soon atterwards undergo. A sniall kind 

 of spider fixes his web in the hollows on the surface of the 

 stone : these webs accumulate, and, with the dust which 

 they collect, form the earthy crust just mentioned, in, 

 which lichens tsouielimes take root, and which naturally 

 retain a constant humidity at the surface of the stones : 

 the frosts then produce considerable injury, and give occa- 

 sion for those raspings, which are in themselves a real de- 

 terioration. 



A plaster therefore became a desideratum, which should 

 fill up the inequalities o*^" the stone without making the 

 angles look clumsy, or deadening the carvings, and which 

 should resist rain and other effects of weather. The late 

 AI. Bachelier had made some interesting experiments on 

 this subject ; and the above committee, aided by his son, 

 have succeeded in producing a plaster which has resisted 

 the tests to which they exposed it, and which gives fair 

 C^rouncJs to expect that our buildings will in future be pro- 

 tected from the causes of decay above enumerated. 



MINERALOGY. 



Our labours i;i mineralogy will appear inconsiderable in 



comparidoa 



