BEN
B I L
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pf comparing them with the camphoric acid,pome chemists having considered these twoacids as nearly identical. The properties ofthe Camphoric Acid will be given under thatarticle; those of tire benzoic are the following:
Ten grains of benzoic acid were mixed with500 grains of distilled water, and shaken in aphial for half an hour. The whole liquid waspassed through a filter, the weight of whichwhen dry was previously known, and after againdrying there was found an addition of 7 \ grainsof weight produced by the undissolved acid.Hence Benzoic acid requires 200 times itsweight of cold water for perfect solution. Onthe other hand it requires only 24 parts of boil-ing water, so that by far the greater part of theacid must again separate on cooling.
An hundred grains of cold alcohol dissolve byagitation about 56 grains of benzoic acid; andboiling alcohol dissolves nearly its own weightof the acid.
Benzoat of Lime. Benzoic acid boiled withcarbonat of lime and water is gradually neutra-lized ; and 50 grains of the acid require in thisway about 20 grains of the calcareous earth, thepure lime of which is about 13 grains. The so-lution when much reduced by evaporation giveson cooling a number of shining silky needledcrystals, often radiating from a common center jtheir taste is sweetish and somewhat earthy.
Though this benzoat of lime is prepared withthe purest acid, and is perfectly white, whenheated by itself in a close vessel it gives a liquidempyreumatic oil, smelling of the resin of ben-zoin. Benzoat of lime requires 20 times itsweight of cold water for perfect solution.
.Benzoat of Potash . This salt crystallizeswhen the acid is slightly in excess, formingsmall needles which require ten parts of coldwater for solution. The neutralized salt ismuch more soluble and deliquescent.
It is to be observed that when most of theneutral benzoats are evaporated, part of the acidflies off, leaving the salt with a slight excess ofbase. This however is not the case with thebenzoat of ammonia, the alkali being full asvolatile as the acid. This property is of someimportance as it gives a reason for a preferenceof the benzoat of ammonia in a very importantuse in analytical chemistry, to which it has latelybeen applied by Professor Berzelius .
This eminent chemist has found that the ben-zoic acid may be applied to the separation of ironfrom manganese, with equal success with theSuccinic , and it has the advantage of being» Journ des Mines. No. lxxxviii. p.
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much cheaper and more easily obtained. It isnecessary for this purpose that the solution con-taining the mixed oxyds should be previouslyneutralized with accuracy, and then the benzoatof ammonia may be added as long as any preci-pitate falls down. This precipitate is merelybenzoat of iron, and all the manganese remainsin solution.
Not only will this salt separate iron from man-ganese, but asM. Hisinger has observed, it willequally, separate it from all earthy salts, andfrom nickel, cobalt and many other metals, noneof which are precipitated by the benzoat whenproperly applied.
(This will be further described in this appen-dix under the article Iron .)
From a recent analysis of this substance byVauquelin, * it appears to be composed of56. Silex29. Alumine2. Lime7. PotashI. Oxide of Iron5. Water
100
It is interesting to observe, that in this mine--ral the character of unctuosity is by no meansindicative of the presence of magnesia. Theanalogy also, as to chemical composition, be-tween bildstein, mica, and felspar, is deservingof notice.
This important fluid has been analyzed byThenard, a a very skilful chemist, who has disco-vered in the bile of some animals what he con-siders as a new animal principle, to which hegives the name of Picromel, on account of itssweet and pungent taste.
The experiments on ox-gall are the following.-A quantity of it was distilled to dryness in a re-tort, by which it lost from to of its weight ofmere water a little flavoured. The dry yellowresidue was calcined carefully in a platina orsilver crucible kept scarcely at a cherry-red, bywhich it gave 22 per cent, of carbonaceous re-sidue containing soda, common salt, phosphatand sulphat of soda, and phosphat of lime.
The uncombined soda amounted to no morethan -zio. of the original gal!,, which appearedmuch too small a quantity to be the intermedewhereby the resin of this bile might be held insolution. Neither is the precipitate formedby acids-at all equal to the whole of the solid247. a Mem. d’Arceuil, tom. i.