260 ANNUAL OP SCIENTIFIC DISCOVERY. 



suffer for the want of coffee. The rapid diffusion and yearly increase of 

 the consumption of coffee is an evidence of the great importance it has 

 attained in social life. 



Whilst, at the beginning of the last century, it was considered a luxury 

 by the higher classes, it has now become a necessary article to all classes 

 wherever food is scarce and dear. Of its total production, which amounts 

 annually to 000,000,000 of pounds, two-thirds are consumed by the 

 Europeans, whose exertions appear so disproportioned to the actual means 

 of nourishment. In the Zollverem States of Germany, the consumption 

 of it amounted, in 1851, to 100,000,000 pounds, or one-sixth of the 

 total production. Upon each reduction of duty, millions of pounds more 

 were consumed by the people, the consumption of coffee and potatoes, 

 from the period of their general introduction, having gone hand in hand. 

 We see the poor instinctively valuing coffee more, the more they are lim- 

 ited to potatoes as their chief food. 



ARTIFICIAL SILICIFICATION OF LIMESTONES. 



It is some years since M. Kuhlmann of Lille proposed to preserve pieces 

 of sculpture, c., by impregnating them with a solution of silicate of pot- 

 ash. SiO 1 KO+CO 2 CaO=SiO 3 CaO+CO 2 KO. This process has been 

 used on a grand scale in certain parts of the Cathedral of Notre Dame. ' The 

 architect of the cathedral reports as follows: 1. That the infiltration of 

 silica made " sur les terrasses et contre-fort du chocur," in October, 1852, 

 has preserved the stone from the green moss that covers stones in moist 

 places : 2. That the gutters and nagging of limestone subjected to this 

 process present surfaces perfectly dry, covered with a silicious crust : 3. 

 That upon the stones so prepared, dust and spider webs are less common 

 than upon the stone in the ordinary state. The report also states that 

 tender stones have been rendered hard ; they have lost part of their porosity, 

 and, after being washed, they dry more rapidly than stones not silicified. 

 The process has succeeded completely on all calcareous blocks, whether 

 isolated or forming part of the structure, new and old. 



It is not yet known how this process will act on mortars ; but if suc- 

 cessful, the silicification of an entire monument may be accomplished, and 

 its restoration when old. The whole exterior might be thus covered with 

 a thick bed of artificial silicate of lime, and a whole edifice be protected by 

 this means from all atmospheric causes of destruction. Silliman's Journal. 



THE STEREOCHROME OF FUCHS. 



The formation of an insoluble cement by means of the soluble silicates, 

 (water-glass,) whenever the carbonic acid of the atmosphere acts on this 

 substance, or whenever it is brought in contact with a lime- salt, has been 

 applied by Fuchs to a most important purpose in the stereochrome. This 

 is essentially a process of fresco, invested with a capability of receiving 



