m Scientific Litelligence, [April, 



by depositionc from the water. Much of the water is constantly re- 

 strained within these reservoirs, and its surface is more or less agitated 

 by the escape of sulphuretted hydrogen gas, and the ejection of 

 water from below. The temperature of some of these springs on the 

 second day of December, between three and four o'clock, p. m., the 

 thermometer standing at 63 degrees, Fahrenheit ; the barometer at 

 29*4, was as follows : — 



The basin of the largest spring particularly designated as " the 

 Caldeira," is circular, and between twenty and thirty feet in diame- 

 ter. The water in this boils with much greater violence than in any 

 other Caldeira, and distinct loud explosions occur at short intervals, 

 which are succeeded by a very perceptible elevation of the centre of 

 the body ol" water within the basin. This is attended with a loud 

 hissing noise, the escape of great quantities of sulphuretted hydrogen 

 gas, steam, and sulphurous acid vapour. On account of the high, 

 temperature, and vast quantities of steam, it is dangerous to ap« 

 proach near this spring, except on the windward side. The cattle, 

 however, are often seen standing on the opposite side, to free them- 

 selves, as it is supposed, from vermin. The peasants are in the 

 habit of placing baskets filled with lupines, beans, and other vege* 

 tables, on the edge of the basin where they are speedily cooked. 



Every interstice in the ground, and the surfaces of many of the 

 loose rocks, are incrusted with sulphur, which is sometimes crystal- 

 lized in acute pyramids, but more commonly in delicate fibres. A 

 considerable quantity of it might be collected in a short time. Silex 

 is deposited from the water under a variety of forms, and many small 

 pieces of pumice and altered lava are cemented by it. — (Dr. Webster's 

 History of the Island of St. Michael.) 



V. On the Solutio?i of Carbonate of Lime. 

 Mr. Dalton,in a paper containing remarks on the analysis of spring 

 and mineral waters, has stated some interesting circumstances res- 

 pecting the alkaline properties of solution of carbonate of lime. It is 

 stated, " that all spring water containing carbonate or super-carbonate 

 of lime, is essentially limy or alkaline, by the colour tests. And this 

 alkalinity is not destroyed till some more powerful acid, such as the 

 sulphuric or muriatic is added, sufficient to saturate the whole of 

 the lime. Indeed, these acids may be considered as sufficient for 

 tests of the quantity of lime in such waters ; and nothing more is 

 required than to mark the quantity of acid necessary to neutralize 

 the lime. It does not signify whether the water is boiled or unboiled, 

 nor whether it contains sulphate of lime along with the carbonate; iti 

 is still limy in proportion to the quantity of carbonate of lime it con-> 

 tains. Agreeably to this idea, too, I find that the metallic oxides, s^ 

 those of iron or copper, are thrown down by common spring watery 

 just the same as by free lime, notwithstanding, this carbonate of 

 lime, in solution in water, contains twice the acid that chalk or lime- 

 stone does. I fully expected the super- carbonate of lime in solution 



* The above are put down in the order in which they were examined. 



