angle, 166 centimetres long and 34 broad; its upper part is a square, each side of which measures 166 centimetres; its perpendicular height is 170 centimetres. The whole should be covered with thick woollen cloth, and placed on some secure foundation. To carry on the operation continually, 18 such vessels are necessary, for it takes 17 or 18 days before the borax is cooled to the proper temperature, viz. that of 30° cent. or 80° Fahr. The place for the crystallization should be separated from the places where the other parts of the operation are carried on, in order that it may not be disturbed by the vessels receiving the least shock; and the temperature of the room ought as much as possible to be invariable, and about 189 cent. or 65° Fahr.

When the crystallization is completed, which is known by the tem perature arriving at the point mentioned above, the lid is removed by the aid of a machine, the mother water is drawn off by a syphon, and then the lid is again closed and kept so for six or eight hours, in order that the heat may be slowly disengaged, and the crystals may not crack by a sudden alteration of temperature. The lid is then again removed, and a workman gets into the crystallizing vessel, and breaks off the crystals, one by one, from the sides. They are afterwards separated and sorted, and the small ones again dissolved. Those which are discoloured by spots of borate of lime or magnesia, are cleaned from these spots by knives and ham mers. The borax is then kept in a dry place, in which a fire is lighted in winter for some days, and is afterwards, › when sufficiently dry, agitated in a basket to rub off the fine angles of the crystals, and make it more like the borax which is purified in Holland. It is then packed up and sent to market. This is one example, though a comparatively trifling one, of the manner in which chemistry has taught men how to make those ar ticles for themselves they before merely gathered from nature, or

imported from abroad. We sup pose it might be advantageous to import boracic acid from Tuscany, and manufacture borax in some parts of Great Britain, instead of continuing to import the article from other countries.

CHEMISTRY AS A SCIENCE. Art, XXI.

ARSENIC. ANTIMONY. WE have already had occasion to mention (Chemist, p. 12, No. I.) that the substance known in commerce by the name of " arsenic," is called arsenious acid, and white oxide of arsenic by chemists. This substance is found native, and is moreover frequently formed in the process of extracting other metals from their ores, and can thus be abundantly procured without further trouble. The basis of this peculiar substance is a metal, and to this metal the chemists restrict the name of arsenic. If the white oxide be fused with twice its weight of soft soap, and an equal quantity of alkali, and it be poured, when fused, into a hot iron cone, the metal will be obtained. Or it may be mixed in a state of powder with oil, and exposed in a matrass to the heat of a sand-bath. This is an offensive process, and can only be performed where there is a brisk current of air to carry off the vapours. The decomposed oil rises first, and the arsenic is afterwards sublimed in the form of a flaky metallic substance. The metal may also be obtained by mixing arsenious acid with half its weight of blax flux, and putting the mixture in a crucible, placing another over it, inverted, and luting both together with clay and sand. Apply a red heat to the lower vessel, when the arsenic will be sublimed and deposited on the inside of the upper crucible. The metal thus obtained has a bluish white colour, somewhat like that of steel, and it possesses a good deal of brilliancy. When heated it emits a strong and very characteristic odour, resembling the smell of garlic. It is one of the softest of the metals, and is so brittle that

it may be reduced to powder in a mortar. When a strong heat is applied it does not melt, but rises in vapour. Water does not affect it, but when exposed to the air it becomes black, and falls into powder. With one of its oxides we have already made our readers acquainted, and of its effects as a poison, under the name of 'arsenic,' they have all heard. In all the states with which we are acquainted with arsenic, it is a poison, though it is prescribed in agues, and with beneficial effects. Realgar,which is a sulphuret of arsenic, is formed by the Chinese into cups, and lemon juice which has stood in them for a considerable time is used as a tonic. Arsenic unites with other metals, and when copper is alloyed with it, it becomes more malleable and flexible, and takes a fine polish. Articles which are to be plated are, on this account, frequently made of this alloy. It forms one of the ingredients also in the specula of reflecting telescopes; and mixed with lead, which it makes more brittle and more disposed to granulate, it enters into the composition of shot. Its oxides and sulphurets are employed by the dyer, they are useful in purifying flint glass; they form valuable pigments, and are of service in many of the arts. As a metal, arsenic is put separately to no use, and seems not individually adapted to any specific purpose.

Antimony, the next metal we have to mention, is employed, as well as arsenic, in medicine, though it is not so violent a poison. There is reason to believe that an ore of this metal was known in the time of the Romans, and was in use as an external application for sore eyes. Admitting the very deleterious nature of some metals, such as arsenic, copper, lead, mercury, &c. it is still difficult to conceive what there is in them so baneful that it cannot be équalled by the productions of the vegetable kingdom, and what therefore has been the source of that prejudice which vaunts the health-giving properties of herbs, and teaches men that

mineral medicines are all to be avoided. We see a considerable number of shops and establishments in the metropolis, particularly in the eastern part of it, for curing all diseases by means of herbs. But surely a man may be as effectually poisoned by hemlock, or hellebore, or laurel leaves, or opium, or nux vomica, or the juice of the upas tree, as by oxide of antimony, or sulphuric acid. There is no ground whatever, therefore, for the prejudice, and disease or painful death may ensue from an improper use of herbs, which is seen even in cattle, as well as from an improper use of minerals. Diseretion, ever-vigilant and watchful discretion, guided by knowledge, is necessary in both cases, and discarding prejudices, whether of antiquity or of present imaginings, we ought to rely on it as our surest and best guide. Long experience has shown that both mineral and vegetable poisons are, in the hands of skilful practitioners, specifics against certain diseases, enabling them to mitigate pain and preserve life. What we have to avoid are those ignorant and pretending quacks and empyrics, who address themselves to our fears and our prejudices, incited by no other motive but to gain their living or a fortune, and never care in this pursuit whether or not the health of their patients is wrecked and their lives sacrificed. We should all take no more medicine than we can possibly help; never take any without its being prescribed for us by somebody who understands the matter, but certainly we should then have no worse opinion of mineral than of vegetable poisons. Some preparations of antimony have been very long in use as medicine, and a few years ago it was. the fashionable specific of the day. Long after the notion of a universal medicine was exploded among sensible men, antimony was raised to that rank by the zeal of its partisans. By others indeed it was as loudly decried, and no poison was supposed to be so virulent as antimony, in all its shapes and forms.

At present men are more sober concerning both its virtues and its deleterious qualities; it is neither a specific for all diseases, nor in all cases a deadly poison; it occupies a more subordinate place in the pharmacopoeia, but still tartarised antimony is classed as a most valuable medicine. Of the virtues of Dr. James's fever powders there seems no doubt, and there is as little that the kermes mineral is a useful medicine, and both these also are preparations of antimony.

What is called antimony in the shops, is a sulphuret of the metal. Ores of antimony have been found in Sweden, Saxony, Hungary, and Norway, and in North America. The pure sulphuretis separated from the earth with which it is contaminated by being exposed to heat in a strong reverberatory furnace, and the metal is afterwards to be obtained by fusing the sulphuret with crude tartar and saltpetre. In this state it was formerly called regulus of antimony, and now simply antimony. In consequence of the disputes concerning its nature, it has been very closely and frequently examined. It is of a greyish white colour, and tolerably brilliant. It has a curious kind of laminated texture, as of thin plates crossing each other, and sometimes it assumes the form of crystals. It is about as hard as gold, and as brittle as arsenic. It melts at a degree corresponding to 810 of Fahr. and at a still higher heat rises in vapour. It is not altered either by air or water, except losing its lustre. But steam, when made to pass over red hot antimony, is decomposed very rapidly and with a violent detonation. It unites with oxygen, and its oxides are used as medicines; it combines also with other metals, forming alloys, some of which are of considerable usc. When combined with iron, it diminishes its magnetic power in a very remarkable degree. A very small quantity of it also destroys the ductility of gold. A proportion of it, not exceeding 1-1920th - part of the gold was found by Mr.

Hutchett to make this metal perfectly brittle. Even the fumes of antimony in the neighbourhood of melted gold are sufficient to destroy its ductility. Great attention was formerly paid to this alloy, because the alchymists thought the quantity of gold might be increased by mixing it with antimony. As a metal antimony is put to no separate and distinct use; but it is one of the ingredients of the alloy of which printers' types, and also of that alloy of which the specula of telescopes, are made. Formerly a sulphuret of antimony was used by the ladies to stain their eye-lashes black; but northern beauties, finding that this was not always an embellishment to their complexions, have either laid aside, or never adopted this cosmetic, and seem, at present, to content themselves with giving to their skins the tints of roses, pinks, and lilies.

ANALYSIS OF SCIENTIFIC
JOURNALS.

ANNALS OF PHILOSOPHY FOR AUGUST.

THE present Number of the Annals is so uninteresting that we are almost sorry to waste on it so much of our space as is necessary to give a brief outline of its contents. Mr. Baden Powell, M.A. F.R.S. continues his remarks on Solar Light and Heat, and condescends to inform us, which is an opinion not remarkably new, nor remarkably well proved, that black bodies are heated more than white ones by the light they absorb. As to his estimate of quantity of light and number of rays, we have no notion how he measured or numbered what can neither be grasped or weighed, and which, though it can be excluded, is not to be divided. Powell's statements are very logical and correct on the supposition that the cause of vision is a distinct substance, and that this distinct substance is reflected in much greater quantities by white than by black surfaces; but according to the general meaning of terms, the propriety is not evident of applying the name of substance to the un

Mr.

known cause of vision, and which has for us no other properties what ever than the single one of making us see. Light is something in perfect harmony with the structure of our eyes, is adapted to them, and, as we know by the blind, has no action whatever for us but through the instrumentality of our organ of vision. To call it a substance is only an example of an eagerness to account for phenomena before they are accurately observed. There is, however, no occasion for this, as the wisest of philosophers and most enlightened observers, they who have pushed their inquiries furthest, and pryed, most deeply into the wonders of the goodly imagery around us all, agree, that wherever our researches may stop, the last fact we can ascertain will be as much replete with wonder, and as much, or indeed infinitely more demand an explanation, than those facts we now endeavour to explain. If this is necessarily to be the end of our researches, as every man of sense knows that it must, why should we jump to it, by inventing explanations, past all the phenomena which lie between our first conceptions and this ultimate conclusion? We wish particularly to caution our readers against the very general mistake of supposing that a phenomenon is explained whenever it receives a name. In almost every branch of science we find curiosity satisfied, and researches stopped by the invention of some pretty sounding noun substantive, on which the mind reposes as if nothing further were to be learned. Calling light a substance gives unnecessary complication to the phe. nomena, at the same time that it checks research by begetting a notion that the matter is already explained. Mr. Baden Powell has only in this respect adopted the general opinion, and has advanced nothing new. It has been stated over and over again, that black surfaces, exposed to the sun, grow hotter than white ones, and we do not see that Mr. Powell, in his elaborate paper has gone a single

step beyond this fact. That what causes vision also causes this greater heat in the black than the white, is by no means proved. We remarked, in speaking of the former part of Mr. Powell's paper, that the sun's rise above the horizon and the spread of light were coincident, while the heating effect of the sun was not brought into action for hours. Even in Mr. Powell's experiments, the white and black surfaces, the reflection from which caused different degrees of heat, were instantaneously seen, while the expansion of the mercury in the thermometer, taken as the evidence of heat, was not complete for a minute. We repeat, then, when effects are not coincident in time, and are so perfectly distinct as sensations of heat and sensations of sight, which every child distinguishes, that it is at least a hasty explanation to ascribe them both to the same cause. For our parts we are willing to admit that both are caused by the sun; but that there is an intervening substance, called light, transmitted from the sun, possessing we know not what sort of properties, but producing both sensations of heat and of sight, seems to us one of those useless inventions with which learned men have in all ages encumbered the beautiful simplicity, and have not explained the phenomena of the universe.

A paper by Sir H. Davy is taken from the Philosophical Transactions, and its substance has already appeared in some weekly publications. Then comes an analysis of the metal of a statue found at Lillebonne, which seems published solely for the purpose of paying a compliment to Sir Humphrey, by contrasting his views with those of M. Vauquelin, and showing that the oxidation of the metal of this statue was occasioned by its having been gilded. The gold and the copper having formed, with the moisture of the earth, a voltaie cir cuit, and thus promoted the oxida tion of the copper. This is a conjecture of M. Labillardiere, and is very ingenious, particularly as cor

roborating and corroborated by the late experiments of Sir H. Davy. In another part of the Annals this subject is again alluded to. We published in The Chemist, No. V,, a letter, disputing in some measure the merit of Sir H. Davy, as to the discovery of his method of preserving copper sheathing; but we accompanied that letter by some remarks, to show, even if the patentee there mentioned had anticipated Sir H. Davy, which we did not believe, the value of the application by the latter gentle man was not diminished, and the principles which led him to it were certainly not known to the other. Mr. Children, in the present Number of the Annals, reverts to this letter, not, however, as it appeared in The Chemist, but in a cotempo-, rary publication, and hastens, with considerable zeal and warmth, to uphold the extraordinary merit of the President of the Royal Society, of which Mr. Children is a member.

We have a very high respect for the illustrious President; but among his partisans and followers, those who belong to his scientific sect, and look up to him and his Society for approbation and support, there is a narrow and jealous apprehension of all other scientific men. Sir H. Davy's merits are so great, that they can only be exalted by just comparisons; and it is both unwise and harsh in those who are immediately connected with him, to show such a feverish anxiety to maintain his superiority. The President must at least be considered as having been born at a very fortunate period, as it gave him an opportunity, which he

in Germany. Dr. Prout, on the acid sometimes found in the stomach, which has already appeared in the periodicals; an account of a rain gauge, an analysis of baryto-calcite, and an astronomical paper, by Colonel Beaufoy. There is no plate; the scientific notices are all old; and the greater part of the articles are mere reprints from other works. Every paper, however, is the production of some person who writes a great many letters after his name, and the editors take special care to inform the world that both are F.R.S. L. and E. F.L.S., &c., as if they supposed learned titles were a security against dulness and ignorance, and that the world would believe, because a man was admitted among the oligarchs of science, that he was both wise and witty.

There is a paper by

TO PREPARE CITRIC ACID.

ACIDUM CITRICUM.

To a pint of lemon juice add as much prepared chalk (about an ounce) as will be sufficient to saturate the juice; mix them, and then pour off the fluid; wash the citrate of lime which remains repeatedly with water; then dry it. Afterwards pour nine fluid ounces of diluted sulphuric acid upon the dried powder; boil for ten minutes; press the liquor strongly through a linen cloth, and filter it through paper. Evaporate the clear fluid with a gentle heat, so that as it cools, crystals may form. To render them pure, dissolve them a second and a third time in water';

ployed, of applying an important discovery, made others. The electricity, and the instruments by which he has risen to famc, do not bear the name of DAVY, but of VOLTA and GALVANI.

There are two papers by Mr. Gray, on the Classification of Insects; two by Berzelius, the Swedish chemist, one on Silica, the substance of which has already appeared in The Chemist; and on the Mineral Waters of Carlsbad,

and set by to crystallize.-Pharmaворага.

GUM MAKES OIL UNITE
WITH WATER.

Ir is said that dried gum, soaked in oil, makes the latter unite readily with water. This takes place even by pouring oil into a mortar, adding water; then throwing in gum arabic, in powder, and shaking or stirring the mixture well.-Bulletin des Sciences Technologiques,