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to be made, and concentrated so that it will mark 10 degrees, equal to about 1071. And to this as much sulphate of copper is to be added as will be equal to one-twelfth part of the galls employed to make the decoction. The several matters being so prepared, six measures of the decoction are to be mixed with four measures of the solution of gum; and to this mixture from three to four measures

of the metallic solution are to be added, by a little at a time, mixing the several matters each time by shaking. Ink so made, will, he says, form no sediment and he estimates the proportions of solid matters contained in it to be five hundred parts of gums, four hundred and sixtytwo parts of the extract of galls and logwood, and four hundred and eighty-one parts of metallic oxides.

Dr. Bancroft, who gives these particulars from Chaptal, proposes the following, as being generally the most suitable proportions for composing the best and most lasting writing ink, viz:

Take of good Aleppo galls, in sorts, coarsely powdered, twelve ounces, and of chipped logwood six ounces; boil these in five quarts of soft water two hours, and strain off the decoction whilst hot; then put to the residuum as much boiling water as, when properly stirred, strained, and added to the former, will suffice to make the whole of the decoction equal to one gallon; add to this five ounces of sulphate of iron, with the same quantity of gum arabic, and two ounces of good dry muscovado sugar; let these be all dissolved, and well mixed by stirring.

A calcination of the sulphate of iron, which Chaptal, Proust, and some others have recommended, Dr. Bancroft does not regard as of much importance; for he says, though the ink may be thereby

made to attain its utmost degree of darkness, almost immediately, yet the strong disposition which ink has to absorb oxygen from the atmosphere until saturated therewith, will enable it, without such calcination, to attain an equal degree of blackness, in a day or two, according to the temperature of the air, if the latter be allowed free access to it. For reasons which he also states, he omits the sulphate of copper; though he observes that, if any portion of that metal were deemed bene ficial, he should prefer verdigrise to the sulphate, the latter containing a much larger proportion of acid than even the sulphate of iron, and being, therefore,

more likely to render the ink corrosive, He regards gum as highly useful to retard the separation and subsidence of its black part, or compound of colouring tion to paper, as well as to hinder it, when matter and iron, previous to its applica used, from spreading and penetrating too far.

Indelible writing Ink.

oxygenated muriatic acid had been found M. Chaptal remarks, that, since the capable of discharging the colour of common writing ink, both from parchment and paper, without injuring their texture, it had been fraudulently employed to efface particular parts or words of deeds, contracts, or other writings, for which others had been substituted, leaving the signatures untouched.

In consequence of society, as well as governments, were these frauds, the commercial parts of solicitous for the discovery of some composition, which might be employed instead of common writing ink, without then minister of the interior of France, its defects; therefore Chaptal, (being and possessed of great chemical science,) self particularly with that subject; and as might be expected, occupied himhe states, that up to the then present time, the composition which had been found most useful for this purpose, consisted of sufficient portion of lamp black and a a solution of glue in water, with which a little sea salt were intimately mixed, by rubbing them together on marble. This composition was made sufficiently thin by water, to flow readily from the pen; resisting the action, not merely of cold, and he describes it as being capable of but of boiling water, and also of acids alkalies, and spirit of wine; and attended with no inconvenience but that of abrasion by being rubbed.

when lamp black has been incorporated It is observed by Dr. Bancroft, that with common ink, by first rubbing the former in a mortar with a mucilage of gum arabic, the writing done with it could not be rendered invisible by the application of muriatic acid; and, doubtless, such an addition of lamp black would hinder the letters from ever becoming illegible by age, at least within any length of time which the paper and parchment could be expected to last. with this addition would require to be But ink made frequently shaken or stirred, as the lamp

black would otherwise be apt to separate and subside.

In the making of indelible ink, the receipt for lamp black before given may be of considerable importance.

Calico Printing.

Perhaps no object has more engaged "the ingenious chemist's art" than this, and leave is craved to conclude this diversion from the mayoralty seal of London, by what may be serviceable to some who are actively engaged in an extensive branch, from whence our private chambers, and the dresses of our wives and daughters, derive continual improvement. Prosubstantive, or Chemical Black, for Calico Printers.

"Some years ago," says Dr. Bancroft, "I purchased of a calico printer, possessing great knowledge of the principles and practice of his art, the secret of a composition which he had employed with success, as a prosubstantive black, and which, as far as I can judge from experiments upon a small scale, deserved the high commendations which he bestowed upon it; and though I have never obtained the smallest pecuniary advantage from this purchase, in any way, I will here give the full benefit of it to the public. The following was his recipe, with some abbreviations of language: viz. Take two pounds of the best mixed galls, in powder, and boil them in one gallon of vinegar, until their soluble part is extracted, or dissolved; then strain off the clear decoction, and add to the residuum of the galls as much water as will be equal to the vinegar evaporated in boiling; stir them a little, and after allowing the powdered galls time to subside, strain off the clear liquor, and mix it with the former decoction, adding to the mixture six ounces of sulphate of iron; and this being dissolved, put to it six ounces more of sulphate of iron, after it has been previously mixed with, and dissolved by, half of its weight of single aquafortis; let this be stirred, and equally dispersed through the mixture, which is to be thickened by dissolving therein a sufficient quantity of gum tragacanth, (of which a very small proportion will suffice.) Calico, after being printed or pencilled with this mixture, should, when the latter is sufficiently dried, be washed in lime water, to remove the gum and superfluous colour, and then either streamed or well rinsed in clear water. This composition

has not been found to weaken, or injure, the texture of calico printed or pencilled with it, and the colour is thought unobjectionable in regard to its blackness and durability."

It is added by Dr. Bancroft, that when sulphate of iron is mixed with aquafortis, the latter undergoes a decomposition; the oxygen of the nitric acid combining with the iron, and raising it to a much higher degree of oxidation; the result of these operations is the production of a fluid which has the consistence and smooth appearance of oil, and which (though the name may not be quite unexceptionable) I will call a nitro-sulphate of iron. I have been induced to believe, from several trials, that a better prosubstantive black than any other within my knowledge may be formed, by taking a decoction, containing in each gallon the soluble matter of two pounds of the best galls, in sorts, and when cold, adding to it for each gallon twelve ounces of sulphate of iron, which had been previously mixed with half its weight of single aquafortis, (of which one wine pint should weigh about twenty ounces,) and, by the decomposition just described, converted to the nitro-sulphate of iron just mentioned. By thus employing twelve ounces of sulphate of iron, oxygenated by nitric acid, instead of six ounces of the latter, with six ounces of the green sulphate in its ordinary state, an improvement in the colour seems, by my experiments, to have been invariably produced, and without any corroding or hurtful action upon the fibres of the cotton."

With these scientific receipts and suggestions it may be agreeable to close. Matters of this kind have not been before introduced, nor is it purposed to repeat them; and those who think they are out of place at present, may be asked to recollect whether any of themselves ever obtained knowledge of any kind that, at some period or other, did not come into use?

NATURALISTS' CALENDAR.
Mean Temperature. 40 72.

February 27.

CHRONOLOGY.

A Scotch newspaper of the 27th of February, 1753, relates, that on the preceding Wednesday se'nnight, the river

Tweed was dried up from six o'clock in the morning to six in the evening, the current having been entirely suspended. On the 20th of February, 1748, the river Sark, near Philipston, in the parish of Kirk Andrews upon Eske, and the Liddel, near Penton in the same parish, were both dry. At the same time other rivers also lost their waters. These remarkable phenomena are naturally accounted for in the "Gentleman's Magazine for 1753," vol. xxiii. p. 156.

NATURALISTS' CALENDAR.
Mean Temperature . . . 41 ·39.

February 28.

Dr. Johnson.

Gin Lane.

The "Historical Chronicle" of the «Gentleman's Magazine," notices that on this day, in the year 1736, a proposal was submitted to the house of commons «for laying such a duty on distilled spirituous liquors as might prevent the ill consequences of the poorer sort drinking them to excess," whereon it takes occasion to adduce the following fact: "We have observed some signs, where such liquors are retailed, with the following inscriptions, Drunk for a penny, dead drunk for twopence, clean straw for nothing." This record establishes the reality of the inscription in Hogarth's fearful print of "Gin-lane," and marks a trait in the manners of that period, which, to the credit of the industrious classes of society, has greatly abated.

It was recorded in the daily journals, Drunkenness exists nowhere but in the on the 28th of February, 1755, that "the university of Oxford, in full convo- vicious or the irresolute. "Give a poor cation, unanimously conferred the degree of man work and you will make him rich." master of arts on the learned Mr. Samuel Give a drunkard work and he will only Johnson, author of the New English keep sober till he has earned enough to Dictionary." Such a testimony to dis- drink again and get poor. While he is tinguished merit, from a learned univer- drinking he robs himself of his time; sity, was, perhaps, such a reward as Dr. drinking robs him of his understanding Johnson appreciated more highly than and health; when he is unfit or disinothers of more seeming worth; the pub-clined to work he will lie to avoid it; and licity given to it at the time is evidence of the notoriety he had attained by his literary labours, and of the interest taken in his fame by every class of society. He taught and admonished all ranks, in a style that charmed by its luxuriant amplification of simple truths, when the majority of people refused the wholesome labour of reflection. Johnson's ethical writings verify the remark of a shrewd writer, that "a maxim is like an ingot of gold, which you may draw out to any length you please."

if he succeeds in deceiving, he will probably turn thief. Thus a drunkard is not to be relied on either for true speaking, or honest principle; and therefore those who see that drinking leads to falsehood and dishonesty, never attach credit to what a drunkard says, nor trust him within reach of their property.

NATURALISTS' CALENDAR.
Mean Temperature... 40. 44.

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