1820.] Phi/sical Science during the Year 1819. 43 



singular agitation, and seems enveloped in a kind of fog, caused 

 by its own dust thrown up in an infinite number of minute 

 explosions. According to Mr. Herschell's analysis, it is a com- 

 pound of two atoms acid + one atom barytes. 



(6.) Hi/posiilphite of Strontian. — This salt crystallizes in flat 

 rhombs, having the plane angles of their more extended surfaces 

 about 64° 45' and 115° 15'; but whose sohd form is that of an 

 oblique parallelopiped, whose sides are inclined to each other at 

 angles of about 76° 30', 96° 45', and 97° 13'. It refracts doubly. 

 At the temperature of 45°, it dissolves in four times its weight of 

 water, while it dissolves in 1-|- times its weight of boihng water. 

 Its taste is purely bitter. It is insoluble in alcohol. It dissolves 

 chloride of silver, and alcohol precipitates the solution in the state 

 of a sweet syrup. 



(7.) Hyposulphite of Magnesia. — This salt is easily formed by 

 boiling a solution of sulphite of magnesia with flowers of sulphur. 

 It readily crystaUizes, is intensely bitter, dissolves readily in 

 water, but does not deliquesce when exposed to the air. When 

 laid on a hot iron it burns with a weak blue flame, but is incapa- 

 ble of maintaining the combustion per se. 



(8.) Hyposulphite of Copper. — This salt may be obtained by 

 digesting hyposulphite of hme on carbonate of copper. It is 

 colourless, has an intensely sweet taste without any metallic 

 flavom-. It is not decomposed by ammonia, nor turned blue by 

 an excess of that alkali provided the air be excluded. Hence 

 the copper in it is in the state of a protoxide. 



(9.) Hyposulphite of Lead. — A white mealy powder obtained 

 by pouring nitrate of lead into a neutral hyposulphite. When 

 held long in the mouth, it leaves a sweet impression. For solu- 

 tion it requires 3266 times its weight of water. At a tempera- 

 ture rather under 212°, it becomes black, and when the heat is 

 raised, takes fire, becoming red-hot, and burns with a weak 

 flame. If it be now removed from the fire, the ignition and 

 combustion may be maintained for any length of time by cau- 

 tiously adding small quantities of the salt. According to the 

 analysis of Mr. Herschell, this salt is composed of two atoms 

 acid + one atom protoxide of lead. 



(10.) Hyposulphite of Silver. — This salt may be formed by 

 adding nitrate of silver to a diluted solution of a hyposulphite. 

 It has an exceedingly sweet taste. In a short time it is decom- 

 posed, and sulphuret of silver is precipitated. 



(11) Hyposulphite of Mercury. — Mr. Herschell's experiments 

 to procure this salt did not lead to very satisfactory results. It 

 seems to follow from them that hyposulphurous acid is cnpable 

 of combining with the peroxide, but not with the protoxide of 

 jnercury. 



Mr. Herschell has shown that the hyposulphite of silver has 

 the property of combining with several of the other hypobulphitcii, 



