1835.J Analysis of Arden Limestone. 97 



It is a compact opaque limestone, with a grey colour and 

 splintery fracture. Its streak is white, and its specific 

 gravity 2*698. 



1. 50*33 grains of this limestone were dissolved in nitric 

 acid. The loss was 21*5 grains, which was chiefly car- 

 bonic acid. 



2. The undissolved matter weighed 7*89 grains. It was 

 fused with carbonate of soda, and analyzed in the usual way, 

 and was found to consist of 



Silica - - - 6-33 

 Alumina - - 1*56 



7-89 



3. The nitric acid solution was evaporated to dryness, the 

 residue was re-dissolved in water, and thrown down by 

 caustic ammonia. A red matter fell, weighing, after wash- 

 ing and ignition, 3 grains, and was peroxide of iron. 



4. The lime was precipitated by carbonate of ammonia. 

 The carbonate being collected, washed and dried, and 

 heated to incipient redness, weighed 39*4 grains. 



Hence, the constituents are 



Carbonate of lime - - - 

 Peroxide of iron - - - - 



Silica 



Alumina 



52-29 „ 99-90 

 When Arden lime, in the state of quicklime is dissolved in 

 muriatic acid, and the solution concentrated, it gelatinizes ; 

 a sufficient proof that the silica, during the burning of the 

 limestone, had combined with lime. To this silicate of lime 

 probably is owing the property which the lime has of setting 

 under water. 



Article V. 

 Notice of some Recent Improvements in Science. 

 By the Editor. 

 One of the most important objects in establishing the 

 present Journal being to afford information in reference to 

 the progress of science abroad* I intend in the following 

 article, which will be repeated from time to time according 



VOL. I. H 



