it. When breathed, even diluted with a large quantity of atmospheric air, it is extremely deleterious, and is fatal to animal life. One of its distinguishing properties is, that it discolours almost all metallic solutions. Some of it was prepared over a water trough, the fluid in which held some metal in solution, and it was gradually discoloured as the sulphuretted hydrogen was formed. From this property it is employed as a test for lead and other metals held in solution, and is in this point very useful. It is perhaps fortunate for the people of this metropolis that most of the compounds of lead are so heavy that they fall to the bottom of water; otherwise the practice of keeping water in leaden tanks, and conveying it through leaden pipes, would prove much more injurious to the health. By its means we can almost always tell if a metal be present, but not so well what metal it is. Sulphuretted hydrogen reddens vegetable blues, and hence it has been called an acid; but this is not a certain test for an acid, as some bodies possessing alkaline properties have the same effect. Gay Lussac has called sulphuretted hydrogen hydrosulphuric acid; but the common sulphuric acid is a hydrosulphuric acid, and the name sulphuretted hydrogen is to be preferred.

When one volume of sulphuretted hydrogen and one and a half of oxygen are fired by the electric spark, decomposition ensues, water is formed, and sulphurous acid is produced. The sulphurous acid is one volume, whence it is inferred that sulphuretted hydrogen consists of one volume sulphur and one hydrogen, the hydrogen being 1 and the sulphur 16; the equivalent for sulphuretted hydrogen is 17, the hydrogen suffering no condensation, and the volume of the compound being the same as the volume of the hydrogen. The gas is also decomposed by passing electric sparks repeatedly through it, when the sulphur is thrown down. In this experiment it would scem that the expansion of the gas

by the heat was the cause of its liberating the sulphur.

Chlorine decomposes the gas also, forming muriatic acid with the hydrogen, and sulphur is deposited. Iodine also decomposes it, forming, in like manner, hydriodic acid, and depositing sulphur. This experiment is of some consequence, as supplying us with the easiest mode of obtaining hydriodic acid, which seems likely to become useful in the arts, from the colouring matter it forms with some metals. The best way, perhaps, of obtaining this acid is to pass sulphuretted hydrogen gas through a mixture of water and iodine. The liquid is afterwards to be concentrated by evaporation, which drives off the excess of sulphur, and liquid hydriodic acid remains. Nitric acid produces, with sulphuretted hydrogen, a deposit of sulphur, forming nitrous oxide.

Sulphuretted hydrogen and ammonia unite in equal volumes, and form hydrosulphuret of ammonia, formerly called the fuming liquor of Boyle, from its having been discovered by him. It is of great use as a test for the metals, and is procured by distilling, in a strong heat, a mixture of 6 parts of slaked lime, 2 muriate of ammonia, and 1 of sulphur. On dropping this substance into a metallic solution it occasions a precipitate, and we can generally know what the metal is by the colour.

Sulphur and nitrogen, as far as we know, have no action on each other, and form no definite compound, though the nitrogen emitted during the decomposition of animal substances appears sometimes to contain sulphur.

Mr. Brande concluded his lecture by introducing the subject of phosphorus to the attention of his auditors. As his remarks were confined to the mode of procuring this substance and to its properties, both of which have already been described in our pages, we shall not repeat his observations, but only give that part of his lecture. which relates to the compounds of

this body, as this is a subject never yet mentioned in The Chemist.

MR. BROUGHAM ON EDUCATION. THIS friend to man generally, and more especially to the working classes of this country,to diffuse education and knowledge among whom he has long laboured, and is now more than ever earnestly labouring, has just published a pamphlet, entitled, "Practical Observations upon the Education of the People, addressed to the Working Classes and their Employers. We should, perhaps, be more zealous in recommending this pamphlet to the notice of our read ers, and encouraging the opulent to distribute it among those who may not be well able to afford it,* were it not that our own labours are mentioned in it among the useful and valuable cheap publications of the day, with more praise than, we are afraid, they deserve. We must not, however, omit to observe, that at present, when so many societies are forming for the diffusion of knowledge, this pamphlet is remarkably well-timed, and contains a great number of most judicious observations as to the principles on which societies should be formed and conducted. We are happy to observe, that Mr. Brougham is a strenuous advocate for the great mass of the people not suffering themselves to be educated, or in other words drilled, by some few of their fellow-men. He strongly recommends that, as they clothe and feed themselves, so they should provide for themselves that species of instruction which they think best adapted to their wants and most conducive to their interests. The management of their seminaries, he also thinks, should remain entirely in their own hands. In these opinions we cordially concur; and having in more than one instance seen the slow-paced, quiet, unimproving and unimprovable uniformity which results from a national education directed by the govern

*The profits are to go to the London Mechanics' Institution.

ment of a country, we must say, there can, in our opinion, be no greater evil, than for a whole community to give up to some few individuals in it the power of prescribing to them what they may, and what they must not, learn. Ignorance is sometimes wisdom; and we would rather see our countrymen, if there were no other alternative, uninstructed than taught mental slavery. Mr. Brougham's pamphlet, in describing what has been already done in this country by the people for their own education, and in laying down the principles on which they ought to proceed, is admirable. The concluding paragraph we shall quote, as holding out,-more perhaps by Mr. Brougham's own example, labouring at night after his irksome professional toils are over, which it records, than by what it says of others, a strong stimulus tô mental industry :

"To the Working Classes I would say, that this is the time when by a great effort they may secure for ever the inestimable blessing of knowledge. Never was the disposition more universal among the rich to lend the requisite assistance for setting in motion the great engines of instruction; but the people must come forward to profit by the opportunity thus afforded, and they must themselves continue the movement once begun. Those who have already started in the pursuit of science, and tasted its sweets, require no exhortation to persevere; but if these pages should fall into the hands of any one, at an hour for the first time stolen from his needful rest after his day's work is done, I ask of him to reward me (who have written them for his benefit at the like hours) by saving threepence during the next fortnight, buying with it Franklin's Life, and reading the first page. I am quite sure he will read the rest; I am almost quite sure he will resolve to spend his spare time and money, in gaining those kinds of knowledge which from a printer's boy made that great man the first philosopher, and one of the first statesmen of

SIR, Having had the misfortune to spill a quantity of ink on a boarded floor, I shall esteem it a great favour, if you will inform me which is the best means of taking out the stain. I have tried a preparation sold for that purpose, also spirits of salt and oxalic acid, but all to little effect, the places turning red according to the test published in The Chemist (p. 151.).

I remain Sir,
Yours, respectfully,
A Reader of The Chemist,

London, Jan. 31.

W.T.

preparing the unguentum hydrargyri fortius, or strong mercurial ointment, by rubbing it in a mortar, with a heavy pestle, with hog's lard. It strikes me that, by this process, it is only subdivided, and that the quicksilver is actually rubbed into the skin in a metallic state.*

Your sincere well-wisher,
J.G.W.H.

The best method of making a clear and lasting red ink?

ANSWERS TO QUERIES. To the Editor of The Chemist. MR. EDITOR,-Having seen in the best method of gilding trinkets, 46th Number, a Query, as to your I send you the following receipts, taken from Mr. Carey's 500 Useful and Amusing Experiments, for making an amalgam, and to gild an alloy :

TO PREPARE THE AMALGAM.

Put a small quantity of gold, quite pure, with about six times its weight of mercury, also quite pure, into an iron ladle, or crucible, which has been previously rubbed put it upon a charcoal fire, and in the inside with whitening, then submit it to a gentle heat, occasionally stirring the metals with an iron wire. The heat should not be so strong as to evaporate the mercury, at least not till the solution of the gold is nearly effected; the heat may then be increased for a moment, till a vapour is seen to rise from the crucible. When the amalgam is formed it is to be thrown into water, where a small quantity of mercury will be seen to separate from it. To free it completely from mercury, it will be necessary to twist it up in a piece of fine wash

*We know it frequently occurs, that the mercury is not oxidized by this process, and consequently it is very often met with in a metallic state in the ointment. The best chemical authorities we are acquainted with say, that experiments the mercury is oxidized or merely meare yet wanted to decide, whether the chanically divided.

side, then pour off the supernatant liquor and bottle it, corking it well. It is now fit for use.

I am, Sir,

Your obedient servant,

A WRITER.

ENGLISH FIRE-SIDES.

We have already pointed out many of the inconveniences of our present mode of heating houses; and as there is no single point of domestic economy more conducive to comfort and health, we are glad to bring before our readers any sug gestion at all tending to improve this part of our system. The prineiple adopted in the stove, of which the following description has been given in the Philadelphia Gazette, has long been known, and may probably be advantageously acted on:

THE COMPENDIUM STOVE. BURNING OF WATER!-Our town (or at least a part of it) has been kept in a state of excitement for three days and a half, by a discovery which has been made of a mode of using water for fuel! The proprietors of coal-mines and woodlands are all in alarm-(by Monday we may expect that the panic will spread among the wood-sawyers and coal-heavers)-the question whether it will be advisable to let the Liberties have the Schuylkill water, now we have this new use for it, already begins to be discussed-and fears have been expressed lest our Professor of Pyrotechny should carry his art so far as to set fire to the Delaware! As he has, however, given his word and honour that before he attempts any thing of this kind he will give suitable notice, so that the ships may be removed,no apprehensions on this score need, for the present at least, be entertained. In the existing state of public feeling, those, perhaps, are most rational who talk of petitioning Council to assess an additional tax on such as burn the Schuylkill water as well as drink it.

Seriously and soberly-Mr. Augustus Day, who resides at No.124,

North Third-street, has invented a stove, by which it has been calculated a room may be kept warni for a whole day, and no more than four cents worth of Lehigh coal be consumed in that period. It is of small size, and in shape an inverted cone, with several longitudinal openings near the apex. On a grate within rests a small quantity of coal. A pan of water placed beneath the openings ensures a constant supply of vapour. In passing through the ignited coal, the aquehave that powerful heat which is ous vapour is decomposed, and we produced by the combustion of oxygen and hydrogen. The cover of the stove is attached to a moveable section of pipe, which is raised and lowered by a fixture similar in principle to that of a suspended lamp, and by this contrivance the fire is regulated. So powerful is the heat, that a small quantity of water thrown into the stove is immediately decomposed, and the combustion of its component parts follows of course. Of this we have ourselves been witness.

The principle of the invention has long been applied in the mechanic arts, especially by the blacksmith, who, as is well known, when he wishes to increase the heat of his fire, throws on it a small qantity of water. Of late years, chemists have, in their compound blow-pipes, made sundry new and very valuable applications of this principle ; but the honour of applying it to domestic economy belongs to Mr. Day alone.

LIFE OF BERTHOLLET.
(Continued from p. 261.)

[ON looking back we see we forgot to state, that we took the Article under this title from the Annals of Philosophy; and we have to regret that this journal now offers so little to us which is either interest

ing or instructive.]

In the course of his investigation into the nature of chlorine, Berthollet discovered chlorate of potash. This he proved to consist of potash united to an acid composed