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Prussian blue, if used sparingly and discreetly, improves the ink by giving it a deeper colour.

Indigo may be employed as a substitute for Prussian blue ; but Mr. Savage is of opinion, that equal parts of each ingredient, mixed with the ink, will give the darkest colour of all. The chances, however, that the ink will receive from the Prussian blue and indigo a " coldish appearance," are very considerable; and he advises that, with a view of guarding against such an effect, a little Indian red should be mixed with the compound. This latter ingredient possesses a depth of colour of a purplish reddish brown, which, blending with the hues of the Prussian blue and indigo, improves the richness and intensity of the black ink. The Indian red is not quite so good for this purpose as lake or carmine, but the preference is due to it from its great comparative cheapness. One of the most valuable articles as a varnish for printing ink is balsam of capivi (copaiba). When old and pure, this balsam, with a due proportion of soap and colouring matter, a stone and muller, will enable any one to make in a moment ink of the most superior quality, without any risk or much trouble. It is difficult to obtain the capivi good. Canada balsam may, in case of necessity, answer as a substitute for the former, but it dries sooner and is much thicker. These balsams, which are of nature's own production, have scarcely any colour, and therefore do not modify in the least the hue of the ink: they dry slowly, which, so far from causing the ink to smear, is really a source of advantage. After this description of the ingredients, Mr. Savage very properly devotes a small space to the description of the implements. An iron boiler is the first essential, and it must be so large as to receive the quantity of oil in a third or half its depth, to prevent the ill consequences of the oil boiling over. The boiler is either suspended over a fire, or raised on bricks with a fire under it; the bricks should elevate it to a convenient height, and they should be so arranged as to keep the fuel from spreading about. The boiler should have a cover capable of being quickly taken off, at the same time that it should be tight. An iron rod, formed like a spatula, is required to stir the oil when the resin and soap are put in, and to convey now and then a portion of the compound out, for the purpose of having its consistency ascertained. A good-sized ladle should also be in readiness to take out a quantity of the oil should it boil over. A stick, of a yard long, with a cleft in one end, into which a piece of paper is inserted, will do very well as a convenient match to set fire to the oil when it is to be burned; and the oil may occasionally be placed in drops upon a piece of slate, plate, or oyster-shell, when the operator wants to determine its state.

Having gone through this preliminary matter, Mr. Savage comes to the most important portion of his work, namely, the details of the results of his own experiments. We are quite sure that the reader will agree with us in the propriety of allowing Mr. Savage to explain, in his own fashion, the method which he deems to be the most unexceptionable:

A boiler being placed upon three brickbats, and surrounded by a circle of bricks, to confine the fire, placed a little apart from each other, to admit a current of air to the fuel, put into it six quarts of linseed oil, then light a coal fire, using plenty of wood in order to make it burn briskly, and keeping it up lively and steady, but not very violent. After the oil has been some time on the fire, it begins to simmer, and small bubbles arise; it soon after has the appearance of boiling, and the bubbles increase in number; but as the oil gets hotter this appearance ceases, the bubbles disappear, and the surface becomes smooth and unruffled; after this it begins to emit smoke; it begins to boil, and it smells very strong; and if the boiling be prolonged, a scum arises: it should now be carefully attended to, and frequently tried with a piece of lighted paper, to see if it will take fire, which it will not do in this state, unless the flame of the paper is carried down to the surface of the oil.

It is a considerable time before it will take fire, but after the smoke begins to arise it should be tried frequently, as it is more manageable when taken as soon as it will burn. When the vapour begins to be inflammable, it takes fire with a few flashes, which may be distinctly heard, although not seen, and these flashes immediately clear away the smoke. In a little time these flashes become stronger, may be seen, and continue flashing a short time : I would now advise that it should be taken off the fire and placed on the ground, set on fire, and kept stirring with an iron spatula, which exposes fresh surfaces to the atmosphere, and keeps the flame in. This burning increases the heat of the oil, and also increases the flame, so that it will be necessary to cover it occasionally, for the purpose of extinguishing the flame, and trying its consistence. This may be done by dipping the spatula into the oil, and dropping a little on an earthen plate, &c. which will soon cool. If it do not draw out into strings, on touching it with the finger, set fire to it again, and keep repeatedly trying it, and continually stirring it up with the spatula; when it will draw into strings about half an inch long, on touching it with a finger and withdrawing it from the plate, it is burnt enough for an ink sufficiently good for book-work generally: the cover should then be placed on the boiler, and the flame extinguished.

If the oil be pushed to a violent boiling heat in the first instance, without trying if it will take fire, the probability is that it will froth so much and rise up in the pot, as to take fire spontaneously by contact with the atmosphere, and become unmanageable, and baffle all attempts to extinguish it, endangering the safety of the building, if within one, and the adjacent ones, and the wasting of the oil. Under these circumstances, when they occur, a large-sized ladle will be found peculiarly serviceable, as a large portion of the oil may be taken out of the pot into the cool ladle, and by taking some out and pouring it into the pot again repeatedly it will rapidly cool, and the oil may thus be saved; and if a few small pieces of soap can safely be introduced without making the oil run over the top of the boiler, it will cause the rising to subside, and thus prevent loss and danger.

I have used a wooden cover to a boiler, made to fit very close, which answered the purpose very well two or three times; but at one time, boiling the oil with a strong fire, it suddenly burst into a violent flame, which set all my endeavours to extinguish it at defiance: for it burnt so furiously that it boiled over, set the wooden cover on fire, and the ground was covered, all round the boiler, with a liquid fire, spreading in all directions in a most alarming manner. I had, as soon as the cover was put on, got it off the fire, by putting a long piece of wood through the bow, and two people lifting it on the ground; throwing water on the burning oil caused it to burn more violently, so I poured water on the ground plentifully, and surrounded the oil with it, so as to prevent the fire spreading, and it thus burnt itself out, without doing any other harm than wasting the oil. The residuum, when cold, had the appearance of Indian rubber, was very sticky and elastic, very tough, and was very difficult to cut with a knife.

I mention this circumstance more particularly, to show how necessary it is to be cautious in boiling oil; how difficult it is to extinguish it when it is burning violently; and the necessity of great care and attention in this part of the process; and that the cover should be made to fit accurately, and be always at hand: for, if such an accident ware to take place within a building, it must inevitably be destroyed.

When the cover is taken off again there is a great quantity of smoke, that has a powerfully disagreeable smell, and a deal of froth : when this froth has subsided, by stirring it well together, six pounds weight of amber resin, or black resin, should be gradually put into the oil, and stirred up: if it were put in at once the effervescence would be so great, that the oil would run over the top of the boiler.

When this is done, and the resin dissolved, which the heat of the oil will do, there should be added one pound and three quarters of dry brown or turpentine soap of the best quality, cut into slices: this also should be put in gradually and with caution, for it causes a violent ebullition, and as the soap dissolves it is thrown up to the top, and forms a kind of froth to a great extent. When all the soap is put in, and the ebullition has ceased, it may be replaced over the fire till it boil, which it will soon do, and the varnish will be completed.

While the resin is being put in, it is advisable to keep stirring the oil with the spatula; the same when the soap is put in, and also when over the fire for the last time, that the whole may be intimately and uniformly incorporated.

Then take five ounces of the best Prussian blue or indigo, or equal weights of each to the same amount, reduced to a powder, and put into an earthen pot or a tub, large enough to contain the whole quantity of ink when all these ingredients are mixed together.

Into this vessel also put four pounds of the best mineral lamp-black, and three pounds and a half of good vegetable lamp-black, then add the varnish, little by little, while warm, and keep stirring it well together, till the whole of the varnish is put in; the stirring of the ingredients together should be continued till they are well mixed and no lumps remain: it should then be submitted to the levigating mill or to the stone and muller, and ground to an impalpable fineness, and the printing ink will be fit for use.

It will be found that if the varnish be cold when the lamp-black is added, a great deal of trouble and loss of time will be occasioned by the difficulty of mixing them; but if the varnish be warm or tolerably hot, they may be mixed much more readily and with comparatively little trouble.

This ink has been compared with the ink of commerce of a celebrated

vol. Ii. (1833) No. Ii. B

manufacturer at five shillings a pound, both as to working and colour, and was pronounced to be fully equal to it in both particulars.—pp. 125—131.

This receipt has, at all events, the quality of being intelligible, and we think that it is one proof at least of the justice which Mr. Savage renders to himself in asserting his right to be considered as a practical man.

Although we have opposed the principle on which the author has so strangely limited the probable sale of his work, still we admit that the most perfect freedom of doing what he pleases with his property belongs to this gentleman. We feel, under these circumstances, that every idea we extract from the work, every passage from it which we present to the public, is in some measure an infringement of its inviolability, and we are therefore called upon in candour and fair play to pause where we have now arrived. In the amount which we have selected, however, we hope that the confines of moderation have not been trespassed upon, as we were guided altogether by a desire to present to the public a fair specimen of the value of the work, and thus, in some measure, counteract the evil consequences so unconsciously brought about by the erroneous plan of the author.

In the remaining pages of this volume are given receipts for fine printing ink. manufactured from the best ink of commerce; for printing ink, of a very superior quality, without oil of resin in its composition; and for printing ink of a very superior quality, in which the varnish is made with oil; the last two chapters treat of coloured printing inks, and of printing inks which change colour on the application of an acid. With regard to the first of these heads, the excellent work of Mr. Savage, on Decorative Painting, produced a memorable revolution in this department of art; and in the present short article he condenses a great deal of very curious and useful information connected with the subject. The other head above-mentioned constitutes the theme of some very ingenious and practical remarks on the very important point of guarding against fraud, so far as it is practised at present on merchants' draughts, and other commercial paper. The principle on which Mr. Savage proposes to establish a suitable guarantee for this purpose suggests to him the expediency of fabricating a printing ink, which would immediately change colour on the application of an acid that might be employed to discharge the writing; so that when it is attempted to obliterate the sum written, in order to put in the figures of a greater sum in its place, the original letters will immediately change colour if the attempt, as is usual, be made with an acid liquid. Mr. Savage then proceeds to give the items of the receipts, first, for a black printing ink that will change colour on the application of an acid; and, secondly, for a crimson ink that will turn in the same way. The work is then concluded by a strong declaration, on the part of the author, that every statement which he has made in the volume is the direct result of his own practical experience.

Art. VTII.

1. — Wages, or the Whip; an Essay on the comparative cost and productiveness of Free and Slave Labour. By Josiah Conder Author of " The Modern Traveller," &c. London: Hatchard' 1833.

2. —A Vindication of a Loan of Fifteen Millions to the West India Planters, showing, $c. fyc. By James Cropper. London: Johnston. 1833.

It was an ingenious thought of Mr. Conder to take John Bull on his vulnerahle side, and to place before his eyes the naked proofs of the possibility of lessening his bills, by hiring instead of kidnapping the poor creatures who cultivate his sugar in some of the hottest parts of his extensive dominions. The prospect of saving a shilling is too much in the nature of an angel visit to be treated with indifference by this long oppressed personage, and if Mr. Conder can only substantiate his very agreeable theory, that it will be cheaper to buy free labour than be obliged to support slave labourers, then we are quite sure that the day will not be distant when honest John will insist upon a change.

Mr. Conder, an advocate evidently for the emancipation of the colonial slaves, is yet prepared, so far as the present pamphlet goes, to give up the prescriptive right (so often, and we regret to say, so excessively indulged in by those of his party,) of abusing the West India proprietors: no, he is content with denouncing the existing practice of holding to slavery, in the colonies, not merely as a crime, but, as Fouche said of the murder of the Duke D'Enghien, it is something worse, namely, a blunder. So that in this brief work, we have Mr. Conder committed, by a voluntary engagement to prove, that slave holding is as unprofitable as it is criminal, that it is as costly as it is unjust, and that, in the long run, it will be found to be a remarkable example of the truth of the well-known maxim, that it is infinitely cheaper to do right than wrong. Mr. Conder's argument is separated into three stages. First or all, he inquires if free labour be cheaper than slave labour; secondly, should free labour prove to be the cheaper, can it be employed in tropical cultivation? can it be employed in effect in growing the sugar cane? thirdly, supposing that both the above questions can be safely answered in the negative, can a sufficient number of free labourers be counted on in the colonies as ready to work in case the abolition of slavery is decided upon to take place immediately?

With respect to the first of these questions, in order to determine the answer that should be given to it, a reference to the exact amount of charges on a West India estate is absolutely necessary, and, truth to say, Mr. Conder's authorities in these matters of fact,

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