Intelligence and Miscellaneous Articles, 467 



chloric acid and treatment of the dry residue with alcohol. The 

 small quantity of pulverulent matter, of a chamois yellow colour, 

 which remained insoluble, consisted of arsenic acid, peroxide of iron 

 and lime. 



The author will not undertake to decide that the acid is combined 

 with these two bases in the deposit ; it being possible that a part of 

 the subarseniate of iron had been decomposed during the operation 

 by carbonate, of lime, of which the deposit from the waters of Royat 

 contains a large quantity. 



Two hundred grammes of this deposit were divided into six por- 

 tions of 33 grammes. Each dose was diffused through honeyed water 

 and] given every two hours to the same dog ; three doses were 

 given in one day and three others the next ; the animal showed no 

 peculiarity during the experiments, and continues healthy and lively. 

 — Journ. de Chem. Med., Septembre 1849. 



EASY MODE OF MEASURING SOLAR OBJECTS. 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 

 I am not aware whether the expedient is generally known of mea- 

 suring the solar spots by placing a graduated glass scale on the dia- 

 phragm of the eye-piece and casting the sun's image upon a white 

 ground. The divisions of the micrometer become thus more palpa- 

 bly distinguished, and the excess covered by the spots is more accu- 

 rately estimated by the eye than when looking direct through the 

 telescope. In this way also an angle can be measured in any direc- 

 tion by merely turning the eye-piece round on its axis. It greatly 

 saves the eye-sight, and is serviceable when only brief glimpses are 

 to be obtained and expedition is required. Although perfect accu- 

 racy may not be attained, it may serve at least for general purposes. 



Should the suggestion seem to you worth noticing, I beg to leave 

 it to your disposal. 



I am, Gentlemen, 

 Edinburgh, Nov. 12, 1849. Your obedient Servant, 



W. Pringle. 



NATURAL SOURCES AND NEW MODE OF PREPARING SULPHURIC 

 ACID. BY M. C. BLONDEAU. 



Abundant sources of sulphuric acid exist in Nature. M. Bous- 

 singault has described several acid waters in America, and particu- 

 larly the llio-Vinagre or Pasiambo, of which 1000 parts contain 2 

 parts of sulphuric acid. According to M. Boussingault's estimate, 

 the Pasiambo supplies 38610 kilogrammes of sulphuric acid in 24 

 hours, and this quantity is much exceeded by the discovery made 

 in the Paramo de Riuzby M. Degenhart, the water there containing, 

 according to M. Lewy's analysis, three times as much sulphuric acid 

 as the Pasiambo. Whence come these enormous quantities of the 

 acid? what are the processes which nature employs in their formation ? 



2 H2 



