Ixii _Hisiorical Sketch of the Physical Sciences, 1818. 
rubbed and carefully wiped. This washing is to be repeated 
till the water comes off quite clean. The borax, thus prepared 
and dry, is to be dissolved in two and a half times its weight of 
water, adding a kilogramme of muriate of lime for every hun- 
dred weight of borax. The liquid is now to be filtered through 
a cloth, and evaporated to the requisite degree of concentration. 
It is then to be put into conical vessels, made of lead or white 
wood, and cooled as slowly as possible ; for the transparency 
and recularity of the crystals depend upon the slowness of the 
cooling.—(Ann. de Chim. et Phys. vin. 359.) 
We are indebted to M. Vogel for some observations on the 
action of borax and boracic acid on bitartate of potash. If 
three parts of the bitartrate and one part of borax be boiled for 
some minutes with a sufficient quantity of water, a portion of 
tartrate of lime subsides. By evaporating the liquid, what is 
called soluble cream of tartar is obtained. It dissolves in its 
own weight of water at 541°, and in half its weight of boiling 
water. Sulphuric, nitric, and muriatic acids decompose it but 
imperfectly. A similar compound is obtained by employing 
boracic acid instead of borax. Bitartrate of soda may be em- 
ployed instead of bitartrate of potash; but the nature of these 
singular compounds is still very imperfectly understood.—(See 
Annals of Philosophy, xii. 113.) f 
5. Carbonate and Hydrate of Lime.—I have no very exact 
idea respecting the compound of carbonate and hydrate of lime, 
which Theodor von Grotthuss informs us is made by passing a 
strong current of carbonic acid gas through lime water. It is 
unnecessary to repeat the phenomena described by him here ;' 
the reader will find a translation of the account given by Grot- 
thuss in the Annals of Philosophy, xii. 51. 
6. Chloride of Lime-—This is the technical name by which 
Mr. Tennant’s bleaching salt must be distinguished in chemistry. 
It is a combination of chlorine and lime; about one atom of 
chlorine to two atoms of lime ; but one half of the lime re- 
mains behind when the powder is digested in water; when 
heated, oxygen is disengaged, and the substance is changed 
into chloride of calcium. This, when dissolved in water, is 
converted into muriate of lime. The chlorine may be trans- 
ferred from the lime to barytes, strontian, and probably also 
magnesia, by double affinity. Thus it appears that chlorine is 
capable of combining not only with the metals, but likewise 
with the oxides and salifiable bases. In this respect it resembles: 
sulphur and phosphorus, which possess the same properties. 
I may here notice that the account which Welther has given 
of the formation of oxymuriate of lime in the Ann. de Chim. et 
Phys. vii. 383, is inaccurate in several particulars. It is a mis- 
take that chlorine will not combine with unslacked lime; but - 
when such a combination takes place, heat is evolved, and un- 
less the increase of temperature be prevented, the continuance, 
