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r-edden litmus. When added to a solution ofgold in nitromuriatic acid with a little drymuriat of lime, the Pyro-acetic ether rises tothe surface with a fine golden colour. In allthese respects this substance resembles the otherethers, but it differs from them in being mis-cible with water in any proportion.

Mr. Chenevix, in the memoir already men-tioned, has examined this Pyro-Acetic Etheror Spirit with much care, and compared itsproperties with those of the true AceticEther. Toobtain the Pyro-acetic Spirit, acetite of lead wasdistilled per se, in an earthen retort, and theproducts again rectified, and the spirit separated.Its properties are the following: It is perfectlyclear and without colour; its taste burning andsomewhat urinous; its smell somewhat re-sembling that of peppermint mixed with bitteralmond. The specific gravity was at first.7929; but after rectification over muriat oflime, .7804. It burns with a white flame,leaving no residue. It boils at 130° Fahr.It mixes with water, alcohol, and the volatileoils, in every proportion ; also in some propor-tions with the fixed oils when cold, and in everyproportion when heated. It dissolves a littlesulphur, more of phosphorus, and a largequantity of camphor. White wax and fat dis-solve in it when hot, but a portion separateson cooling or on adding water. It dissolves alittle caoutchouc which is separable again bywater, and it renders a solution of gum arabicextremely turbid.

A further examination of this spirit by distil-lation with potash and with the mineral acids,shews some decided points of difference be-tween the Pyro-Acetic Spirit and the AceticEther prepared by acetic acid and alcohol, but afuller analysis is yet wanting.

Some chemists have attributed the productionof an inflammable spirit during the distillationof rhe acetites to that portion of alcohol whichall vinegar contains, and is derived from thevinous fermentation which always precedes theacetous. It is certain that when a large quan-tity of vinegar is distilled, the first portionscontain a little alcohol intimately mixed withthe acid. But this alcohol comes over at thefirst impression of heat, and certainly cannotbe supposed to enter into the composition ofthose solid acetites (verdigris for example) thatrequire long ebullition of die acid and metallicoxyd, and subsequent evaporation to crystallize.Yet it is from these solid acetites that thePyro-acetic Spirit is prepared, and it rises onlytowards the middle and end of the distillation,

when a heat much greater than is required tovolatilize alcohol has been kept up for a con-siderable time. This Pyro-acetic Spirit or ethertherefore, is obviously a product of the decom-position of some of the component parts of theacetous acid itself, and not an adventitious ad-mixture of alcohol derived from the previousfermentation.

For some further remarks concerning the trueacetic ether, see the article Alcohol in thisAppendix .

Acetate of Alumine.

Gay-Lussac has some valuable observationson this salt, which are particularly useful to 1 thedyer and calico-printer, who employ a vastquantity of it. When a solution of acetitedalumine is heated, it becomes turbid and depo-sits a great deal of alumine ; but (what is veryremarkable) all the alumine is gradually redis-solved on cooling and agitation. A secondheating will again cause the alumine to preci-pitate, and the liquor will again become'clearwhen cold ; and this may be repeated an inde-finite number of times. In a neutral solutionof acetited alumine (such as is made by thecalico-printers, by mixing alum and acetitedlead) the author found that the quantity of alu-mine separated by mere heat was nearly halfthe whole contents. After the alumine isdeposited from the heated solution, the liquorremains with an excess of acid, and hence thenecessity of using chalk to saturate this excess,which however is often an injurious addition bnother accounts. Alum will prevent this sepa-ration of alumine by heat.

ACETIC ETHER and SPIRIT. See thepreceding article and Alcohol.

ACIDS VEGETABLE. See Analysis.

ACTINOTE. See Amphieole.

AEROLITE or Meteoric Stone.

That stony masses, sometimes solitary, some-times in showers, have fallen on the surface ofthe earth from the upper regions of the atmos-phere, is a fact, which, though distinctly andparticularly testified both by ancient historiansand more modern observers, had gained butlittle credit among philosophers previously tothe last twenty years. On some particularoccasions indeed the evidence adduced was socircumstantial and apparently unprejudiced thatnothing but the supposed impossibility of thefact prevented its reception. In the meantime new facts bearing a perfect analogy withthe preceding ones continued to accumulate,and with such overpowering evidence that alla priori arguments gave way before them, and