An account of the most important recent discoveries and improvements in chemistry and mineralogy, to the present time : being an appendix to their Dictionary of chemistry and mineralogy

Appendix

TO Tlinu

DICTIONARY OF CHEMISTRY AND MINERALOGY

By a. & C. R. AIKIN.

LONDON :

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In the following pages (intended as an APPENDIX to their Dictionary of Chemistry and Mineralogy) the authors have endeavoured to give a perspicuous and sufficiently detailed account of the various and highly important discoveries by which the science has been enriched during the few years that have elapsed since the publication of their former volumes.

Considerable pains have been taken in verifying calculations ; in collecting valuable but diffused information into one focus ; in stripping it of the occasional acerbity of controversy ; and in moulding the whole to that form of practical utility, which may best secure it from being superceded by future discoveries.

We trust that the purchasers of the Dictionary will not find the present Supplement unworthy of their notice.

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A

A C A

-/\.CANTICONE* See Amphiboly.

ACETIC ACID* Acetites. Vi^ecar.

M* Cadet* hag made several expenments on the manufacture of sugar- vinegar and the best proportions of ingredients* Tt is well known that pure sugar dissolved in water will not ferment by itsclfj but if yeast or leaven be added, fermentation is soon estriblished, at first vinous, afterwards acetous* Mucilage, Extract, Fecula contributed materially to the products of fermentation, but M* Cadet has apparently been compelled in order to simplify the enquiry, to pass over very slightly the effects of these substances, and to confine himself to the Operation of sugar alone. His results therefore can only be considered as affording some approximation to accuracy. To form a simple sugar vinegar he gives the following as the best proportions • Sugar * * . , 12A.

Leaven or Yeast • 8*

100*0

When a much greater proportion of sugar is added, a portion of it escapes fermentation, and may be procured from the vinegar unaltered. Though alcohol is. the leading product of the vinous fermentation, and therefore (telerh pa^ ribus} the more alcohol ^ fermented liquor contains, the greater quantity of acetous acid it will produce, yet the addition of alcohol to the fermenting liqpor will not encrease the product of acetous acid, and if more than about of

* An* Chim, tom* St

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alcohol be added, the fermentation is entirely stopped and no vinegar is formed*

In making vinegar in the large way, from whatever vegetable material, whether wine, cyder, grain, carrots, sugar, &c. M. Cadet advises a previous essay of about 8 ounces of the material (if dry) with 3 pounds of water and ^ oz. of yeast fermented completely into vinegar. To this is to be added gradually a solution of caustic potash of known strength, till the liquor is saturated fas determined by litmus, &C*) and the quantity of solid potash noted* Then for every part of potash used he estimates 1,268 parts of sugar to have been acidified by the fermentation, and hence the saccharine strength of the materials is found. Then to produce the strongest possible vinegar without leavings any undecomposed sugar, he proposes so much sugar to be added to the materials (if deficient in this principle) as will raise the proportion t6 12 A per cent, of the whole fermenting mass, which (with the 0.8 per cent, of leaven) produces as above mentioned the most favourable proportions for this manufacture.

The density of acetic acid cannot be depended on singly as any indication of the strength of' acidity* On this subject M. MoJIetat has some valuable observations. ^ The strongest acetic acid that he could obtain, which was quite pure* and free from empyreuma, had the specific gravity of J .063 at 60'^ Fahr. This was highly volatile when moderately heated, and entirely congealed at about 55^^, arid did not thaw at 72^, A given portion of it saturated 250. of carbonat of soda, and its proportion of real acid

A

A C E

A C E was reclconed at S7.1i?3 per cent. A mixture of the same acid and water in a certain proportion was made, which had exactly the same specific gravity, but its saturating power was only equal to I IS of carbonat of soda, or 58.725 real acid. A further addition of water to this last acid dim ini sited the density as well as the saturating power, and this continued uniformly in every subsequent proportion of water added. On the other hand the first addition of w ater to the concentrated acid of l.Ofiy sp.gr. cwcreased the specific gravity, though the proportion of real acid was of course diminislhed. Hence there must be a point of the maximum of specific gravity in which the gravity w^ould be lessened both by encreasing and diminishing the real strength of the acid as measured by its saturating power. This m5i?:imum of density M. Moilerat estimates at 1.0791 sp. gr. and 67.250 per cent, of real acid. ^

The observations of M.Derosne, M.Bcrthollet and Mr. Chenevix, which we shall presently mention, confirm this fact of a maximum density existing in this acid in a certain state of dilution. These observations however^ only apply to the acetic acid or radical vinegar obtained from some of the neutral acetates. The common distilled vinegar contains a quantity of carbonaceous matter whicli can only be separated by combining it with a basis and redistilling it.

Mr. Chenevix ^ has given a valuable experimental essay on acetic acid and some of the acetates. A quantity of acetite of copper w'as distilled per se, and tlie product separated as it came over into different portions. The first portion had the specific gravity of 1.0659, and the proportion of real acid estimated from its saturating powder was 62.971. The s 2 cond was 1.058 sp. gr. and 67.46 1 acid : the third, 1 .0454 sp. gr. and 74.411 acid j the fourth, 1.040 sp. gr. and 73.295 acid.

Though these numbers do not exactly cor^ respond with those of M. Moilerat, they shew that the specific gravity of acetic acid is no indication of its strength in real acid, and the reason of this is supposed to be the admixture of a portion of an inflammable spirit in various proportions formed during the distillation of the acetites, which has been examined by various chemists, and which the author terms Pyro-acelic Spirit; and M. Derosne, Pyro* gleet ic Ether*

The products of the distillation of the metallic^ alkaline and earthy acetates differ remarkably in the proportions of the acid, pyro-acerit spirit, and gasseous products, though the acetates themselves are all prepared with the same acetic acid. Hence it becomes an interesting enquiry to examine what is the action of these bases on the acid during distillation, w'hich can explain this great difference in the products. The analysis is complicated and attended with many difficulties, but the experiments of Mr. Chenevix on this subject deserve notice. The metallic acetates examined w^erc those of silver, .copper, nickel, lead, iron and manganese. A given quantity of each W'as distilled from a luted earthen or glass retort according to the heat required, to w'hich w^as attached a tubulated matrass to collect the liquid products, a Woulfe bottle holding a solution of pure barytes, and a pneumatic trougli. The heat was kept up as low as possible to eflect the decomposition. The results consisted therefore of three substances which required a subsequent examination, namely, the metal or metallic oxyd left in the retort, the liquid, and the gasseous products. The metallic residue was reguline in some cases and oxidated in others, and mixed with a small portion of charcoal wffiich W'as separated by dissolving the metal.

The liquid product was examined in relation to its specific gravity, its acidity, and the quantity of pyro-acetic spirit. The force of acidity was measured by the quantity of a solution of pure potash saturated by a given portion of the acid. It W'as more difficult to separate the pyroacetic spirit. When alcohol is mixed with any watery liquid, the usual mode of detecting it is by the addition of carbonate of potash, but where the liquid also contains an acid which by union with potash forms a salt soluble in alcohol, this mode of separating the spirit w'ill not answ'er. It was therefore necessary in the present instance to redistill from potash the liquid products of some of the acetates, and thus deprive them of their acid, before the spirituous portion could be obtained. We shall add the results of these experiments as far as concerns the liquid product in the three circumstances of specific gravity, acidity and spirit.

Sp.Gr. Acidity Spirit Acetite of Silver . 1.0656 107.309 0.

Acetite of Manganese .8264 1.285 0.94

« Ail. Chim. tom. 69.

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Of these acetites the metallic bases of the four first were left after the process in the reguline state, the iron was the black oxyd, the zinc the white oxyd, and the manganese the brown oxyd. The enormous difference in strength of acidity which these products sliew, must immediately strike the reader. The author inclines to the op nicn that in proportion to the greater difficulty of the reduction of the metallic base is the quantity of spirit yielded and of acid destroyed. Tlius the acetite of silver which is reduced wiih the greatest ease, gives an acid of much greater strength than the others, but no ascertainable quantity of spirit. On the other hand the acetite of lead, which is reduced with more difficulty, and the acetite of zinc which is not reduced at all, give a very weak acid but more spirit. It must be acknowledged however that the production of spirit bears no proportion to the destruction of acid, so that no argument can be hence derived of the conversion of the latter into the former.

When the acetites of potash and of soda are distilled per scy they yield a more vSpirituous and less acid product than any of the metallic acetites. The product from dry acetite of barytes had the specific gravity of only .8158, did not redden vegetable colours, but contained so concentrated a spirit that it was necessary to add water to enable carbonat of potash to produce any separation of spirit, and then the quantity of spirit separated was more in bulk than the entire original product of the distillation. Hence the spirit was in a more condensed state before, than after the separation. Mr. Chenevix has found the acid product distilled from acetited silver to contain the purest and strongest acetic acid and the least mixed with spirit. Its specific gravity was 1.0656 when undiluted, and its saturating power estimated at 107.309. When gradually lowered by water, the specific gravity at first encreased to 1.0733, but after this point again diniinished by every subsequent dilution. This anomaly in the change of specific gravity cannot be accounted for Jiere by the presence of pyro-acetic spirit, since none was detected, and the author therefore ingeniously attributes it to the strong tendency of crystallization at a moderate temperature, which this very concentrated acid possesses, and which probably acts as it does with water to produce an expansion of the liquid as it cools down to its point of congelation. The fact of the ready crystallization of the acid is undoubted, and this appears not to be owing to the presence of any spirit or extraneous matter, but rather to depend on the degree of concentration of the acid itself.

It has been maintained by some chemists^ that prussic acid and ammonia are among the products of the distillation of the acetates. This however is denied both by Mr. Chenevix and by Tromsdorff. The latter chemist ^ distilled acetite of soda, acetite of lead and acetite of potash, separating the volatile portion from the residue. The former was passed tlirough an ignited tube, and carbonic acid, carburetted hy-* drogen and empyreumatic oil were produced, but no prussic acid nor ammonia appeared either in this or in the fixed residue.

The latest analysis of acetic acid that we possess, is one of a very interesting series on various animal and vegetable substances, performed by Messrs. Gay-Lussac, and Thenard.** The mode of analyzing is original,being by combustion with oxymuriat of potash, as will be further described under the article Analysis. The acetic acid was procured from acetite of potash by sulphuric acid, without any artificial heat, and the acid obtained was quite free from any admixture of the sulphuric. It was first boiled with carbonat of barytes, and the resulting acetite of barytes dried in the heat of boiling water. ^ Thirty grammes of this salt were dissolved in water and decomposed totally by sulphat of ammonia^ and the sulphat of barytes, when ignited, weighed 25.445 grammes, of which the barytes, according to the received proportions, forms 67 per cent, and hence the composition of the acetited barytes dried at a boiling water heat, is 43.17 per cent, of acetous acid, and 56.8^ barytes.

This acetite was then ignited with oxymuriat of potash, and the acetic acid when reduced to its ultimate elements, carbon, oxygen, and hy«- dre^en, gave the following proportions:

Carbon 50.224, oxygen 44.147, hydrogeqs 5.629,

Or, supposing all the hydrogen to be united to its saturating proportion of oxygen to constitute water, the result will be.

Carbon 50.224, water 46.911, oxygen in excess 2.865.

Four other vegetable acids were analyzed by these chemists in the same manner, namely, the oxalic, the mucous, the tartaric, and the citric, and the general results are as follow :

* Rccherches Physico-Chimiques, &c. tom. e,

a2

* Au. Chim. tom. 58.

ACE ( 4 ) ACE

Oxygen in each. Carbon. Water. Oxalic dO.oO — 33.57 ~ 2^i.S7

These analyses, if correct, give a totally different idea of the constitution of the acetic acid, compared with the other vegetable acids, from lliat usually entertained. It has been maintained by Westrumb, Hermbstaedt, Crcll, and others, that the pure acid of vinegar was the ultimate term of oxygenation of all the vegetable acids, Co that any other of these could be converted into the acetic by an oxygenating process. Thus Hermbstaedt converted the dry acid of tartar entirely into the acetous, by distillation with manganese and sulphuric acid, f See arlicfe Acetous Acid ^ (Ji. Diet. voL J, p. 4t.) But on the other hand the above experiments of iVIessrs. Gay-Lussac and Thenard shew that the acetic acid is by far the least oxygenated of the five vegetable acids here mentioned, but contains a much larger proportion of carbon, and lienee one may expect the acetic acid to be among the . earliest products of any acidifying process going on in vegetable matter. This, they maintain, is supported by actual observation, for the acetic acid is that into which all vegetable and even animal matter is the soonest changed, whether by distillation or the putrid fermentation, or by the action of the nitric and sulphuric acids. How, say they, should these changes take place (especially that of wine into vinegar) and no intermediate acid be found, if the acetic acid was the most oxygenated.

P^ro-Acetic Spirit. Puro-Acclic Ether. This substance having already been partially described in our account of Mr. Chenevix’s experiments, and also having been previously examined by Derosne,* we shall here add some further notice of it. It is contained, as already mentioned, in the product of the distillation per se^ of most of the acetites, and it is probably in many cases owing to the admixture of this spirit that tlie specific gravity of the distilled liquid is so much lessened as to counteract the increased density which would naturally arise from a great intensity of acid. M. Derosne obtained it in the following experiments, which were also undertaken as a general examination of the products in the usual way of preparing vcetic acid. An earthen retort was filled with

41|lbs. (French) of verdigris, and distilled per sc, in a very gradual heat kept up for three days. The products were divided into four successive portions, each of which was kept separate. The first portion weighing 3 lbs. JOoz. was weakly acid to the last, and of a slight blue colour.

The second was stronger and deeper coloured, and weighed 6 lbs. 4oZj.

The third, sri 11 stronger and more blue, had a much mOre puWeilt smell, but rather empyreumatic., . ft yfeijglied 7 lbs. 4oz.

The fourth was'sTiglitly yellow, had a weak hut very empyreumatic smell, and required a very strong heat to be expelled. It weighed

oz.

The united weight of these four liquids was 20 ibs. 5 oz. and the cupreous residue in the retort weighed 131b. 14 oz. so that there wn$ a deficiency of 7 lb. 5 oz. to make up the origiginal weight of the verdigris employed.

A large quantity of gas was produced in the operation, the whole of which was made to pass through a separate bottle of distilled water before it escaped, to which it gave some acidity and a very disagreeable burnt flavour.

The four distilled products were again rectified and divided into succes.'^ive portions, and by comparing the specific gravity of each with the power of saturating alkali, it was found that the second and third products, or those wliicli were obtained at the middle of the first operation, were much the strongest in acid with the least specific gravity. This intermediate product being rectified at a gentle heat, gave a quantity of inflammable gas, and a light inflammable liquor, but still acid. To separate ihe acid, solid caustic alkali was added to it iti small portions, keeping the vessel in cold water till the acid was saturated, when part of the acetited potash crystallized spontaneously, and a light yellowish liquor rose on the surface, which was carefully decanted and again rectified by distillation at a very gentle heat. The product of this last operation is the Pj/ro* Acetic Ether.

It is quite clear and colourless, its smell pungent, its taste hot and empyreumatic. It is lighter than alcohol, very volatile, and produces cold by evaporation. It is highly combustible, burning with a flame at first blue, afterv/ards yellowish white. After its combustion it leaves a carbonaceous stain, and if previously mixed uith a little water and burned, the water remains slightly acid. It docs cofc

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A E R redden litmus. When added to a solution of gold in nitvomuriaiic acid with a little drjr tnuriat of lime, the Pyro-acetic ether rises to the surface with a fine golden colour. In all these respects this substance resembles the other ctherSj but it ciidVrs from them in being miscibie with water in any proportion.

Mr. Chenevix, in the memoir already mentioned, has examined this I^yro-jlcclic JEiher or Sph'it with much care, and compared its properties with those of the true AceticEther. To obtain the Pyro-acetic Spirit, acetite of lead was distilled per sCy in an earthen retort, and the products again rectified, and the spirit separated* Its properties are the following : It is perfectly clear and without colour j its taste burning and somewhat urinous; its smell somewdiat resembling that of peppermint mixed with bitter almond. Uhs specific gravity was at first .79S9; but after rectification over muriat of lime, .7864* It burns v/ich a wdiite flame, leaving no residue. It boils at 130^ Fahr. It mixes with water, alcohai, and the volatile ojIsj,, in every proportion ; also in some proportions with the fixed oils when cold, and in every proportion when heated- It dissolves a little sulphur, more of phosphorus, and a large quantity of camphor* White wax and fat dissolve in it when hot, but a portion separates on cooling or on adding water* It dissolves a little caoutchouc which is separable again by water, and it renders a solution of gum arable extremely turbid*

A further examination of this spirit by distillation with potash and wiih the mineral acids, shews some decided points of difference between the Fyro-Acetic Spirit and the Acetic Ether prepared by acetic acid and alcohol, but a fuller analysis is yet wanting.

Some chemists have attributed the production of an infiammable spirit during the distillation of the acetites to that portion of alcohol which all vinegar contains, and is derived from the vinous fermentation which always precedes the acetous. It is certain that when a large quantity of vinegar is distilled, the first portions contain a little alcohol intimately mixed with the acid. But this alcohol comes over at the first impression of heat, and certainly cannot be supposed to enter into the cor^^sition of those soiid acetites ("verdigris for ex^ple) that require long ebuiHdon of the acid and metallic Oxyd, and subsequent evaporation to crystallize, Itet it is from these solid acetites that the Pyro-acetic Spirit is prepared, and it rises only towards the middle and end of the distillation, when a heat much greater than is required to volatilize alcohol has been kept up for a considerable time* I bis Pyro-acetic Spirit or ether therefore, is obviously a product of the decomposition of some of the component parts of the acetous acid itself, and not an adventitious admixture of alcohol derived from the previous fermentation.

For some further remarks concerning the true acetic ether, see the article Aicokoi in this Appendix*

Acetaie of ylhi m we,,

Gay-Lussac has some valuable observations on this salt, which are particularly useful to the dyer and calico-printer, who employ a vast quantity of it When a solution of acetited aluniine is heated, it becomes turbid and deposits a great deal of alumine ; but {what is very remarkablej all the alumine is gradually redissolved on cooling and agitation. A second heating will again cause the alumine to precipitate, and the liquor will again become clear when cold ; and this may be repeated an indefinite number of times* In a neutral solutioir of acetited alumine (such as is made by the calico-printers, by mixing alum and acetited lead) the author found that the quantity of alumine separated by mere heat was nearly half the whole contents. After the alumine is deposited from the heated solution, the liquor remains with an excess of acid, and hence the necessity of using chalk to saturate this excess, which however is often an injurious addition on other accounts. Alum will prevent this separation of alumine by heat.

ACETIC ETHER and SPIRIT* See the preceding article and Alcohol.

ACIDS VEGE TABLE. See AN.\Lysis, ACTINOTE. See Am phi bole* AEROLITE or Meteoric Stone*

That stony masses, sometimes solitary, sometimes in showers, have fallen on the surlace of the earth from tlie upper regions of the atmosphere, is a fact, which, though distinctly and particularly testified both by ancient historians and more modem obser^rers, had gained but little credit among philosophers previously to the last twenty years* On some particular occasions indeed the evidence adduced was so circumstantial and apparently unprejudiced that bothing but the supposed impos ability of the fact prevented its reception. In the mean time new facts bearing a perfect analogy with the preceding ones continued to accumulate, and with such overpowering evidence that all a priori arguments gave way before them, and

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AER ( G )

llie existence of atmosplieric or meteoric minerals is fully admitted.

Ill the article uatice Iron, among the ores of tliat metal, the reader may find a few details relative to tliis subject *, and a reference to another article Stones viclcoric v/hich by some unaccountable oversight is wholly omitted. This omission it is the purpose of the present article to supply.

Without adverting to the testimony of Livy, of Pliny, and of other ancient authors, I shall confine myself to a brief enumeration of tliose aerolites wliich have either fallen within the last twenty or thirty years, or of which, though the date of their fall is considerably more ancient, specimens are still extant, many of which have of late been submitted to chemical analysis.

Those luminous bodies called meteors or fire-balls, which make their appearance at irregular intervals, traversing with an excessively rapid motion the upper regions of the atmosphere, and ultimately falling on the surface of the earth, appear to be one source of meteoric stones. They evidently consist of a central nucleus in such a state of softness or fluidity as to admit of considerable variations in its shape ; sometimes a disruption of the nucleus takes place, accompanied by an explosion, and the two or three pieces into wdiich the mass is thus divided proceed in the direction of their previous course without any apparent abatement of velocity. More usually however the explosion is so violent as to break and disperse the meteor, and the fragments immediately fall to the ground. Of these meteors some of the most remarkable and the best observed in modern times are the following. On the 21st of May, ]()7(), a meteor w^as observed by Montanari, professor of mathematics at Bologna, and by others, passing with great velocity across the north of Italy in a direction nearly from E. to W. When it had arrived over the bca to the S.W. of Leghorn it burst with a violent explosion, and its fragments, as they fell into the sea, produced a hissing noise like that occasioned by plunging red hot iron into water.

On the JJth November, 17(}l, a meteor w’as observed in several of the provinces of Trance. It burst with a loud explosion into a great number of fragments in the neighbourhood of Dijon, one of wdiich fell upon a house and «ct fire to it.

On the 17th July, 1771, a meteor, traversing from N. toS. w^as observed in England and in France. It burst with a loud e.xpiosioa S.W.

of Paris, causing a commotion like that of an earthquake. Its elevation above the surface of the earth, when first perceived, was more than 80,000 yards, but at the period of its explosion it had descended to about half its former elevation.

On the 18th August, 17S3, a large meteor, traversing in the same direction as the preceding, w^as observed in various parts of England, of France, and of Italy as far as Rome. When it first was noticed, its apparent magnitude was about equal to that of the planet Jupiter, but it rapidly increased, and at the instant of its explosion w^as of greater apparent magnitude than the full moon. Its form varied from round to oblong, and an internal movement like that of ebullition w^as distinctly visible : it divided into several smaller masses, which continued in their onward course before the final explosion by which it was dissipated. The rate of its motion, according to the lowest estimate, w^as about 1;^ mile in a second.

Tlie diameter of the nucleus of those meteoric bodies is variously estimated at from 100 to 1000 yards ; and it is obvious that a body of much inferior size, moving with an equal or nearly equal velocity, would fail to attract notice, especially in tne day time, except at the period of its actual explosion. The greater number of instances of the fall of meteoric stones are under circumstances which render it probable that they too are occasioned by tlie exploding of meteors, which their inferior magnitude alone prevents from being visible. A loud noise, like that of thunder or the firing of heavy artillery, or the overturning of a load of stones, sometimes with, often without any visible flash, is the first circumstance which attracts notice and excites alarm, then a hissing like the noise occasioned by the passage of a shot through the air is heard j a momentary glances q{ the falling bodies is caught, and they are perceived entering the surface of the soil, the grass and mould being at the same time thrown up on all sides, and a sulphurous odour diffusing itself to some distance around. On immediate search being made, by digging in the direction of these holes, there is found, at the depth of a foot or two, a black roundish stone, sometimes large sometimes small, often too hot to be held in the hand, and smelling strongly of sulphur. Such are the general phenomena j tlie most remarkable examples are as follow :

1. In the year 1492, according to Sebastian Brandt, there fell from the sky at Ensisheim in

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Upper Alsace, a large somewhat oval stone, which from this extraordinary circumstance was kept attached to a chain in the cathedral of that place. The weight of the stone was about 2 cwts, externally it was rough, dull, and of a dark colour. On being broken, it presented a close grained texture and a blackishgrey colour, and contained interspersed confusedly crystallized grains of yellow pyrites, and of grey scaly non-sulphurous iron ore attractable by the magnet, and therefore approaching to the metallic state. The specific gravity of the stone was 3.2 : it did not give sparks with steel, and was pulverized without dilficulty. It was analyzed by professor Barthold in the year 1797, but this analysis being performed on the entire stone, and not separately on the three substances of which it visibly consists, we can only gather from the result, that it consists of silex, aliimine, magnesia, iron, sulphur and a little lime. The conclusion of tlie professor is, that the stone of Ensisheim is a common argillo-ferruginous mineral, and that its traditionary origin is a mere superstitious fiction.

2. On the 3d July, 1753, a shower of stones, each weighing from one to twenty ibs. and upwards, was said to have fallen during a thunder-storm at Plann near Tabor in Bohemia. One of these was deposited by Baron Born in his cabinet and described in his Lithophylacium pt. I. though he considered the account of their origin to be an idle story •, and the cabinet of Baron Born coming into the possession of Mr. Grcville, the specimen in question was found to form a part of it.