and about seventeen of them comprized within the great division we have now described, twelve to the westward, and five to the eastward, of the Shannon; and of the remaining three parts, about two are to the south, and one to the north, of this division. Of the positive amount of their contents we have as yet no data that can enable us to speak with any precicison; but we are led to believe, from various communications with our engineers, that the bogs in the eastern division of the great district above described amount to about 260,000 English acres, which, on the proportion already mentioned, would give rather more than one million of English acres as the total contents of the bogs of Ireland; excluding however from consideration mere mountain bogs, and also all bogs of less extent than 500 acres, of each of which description the amount is very considerable of the extent of the latter some idea may be formed from a fact which we have learned from Mr. Larkin; that in the single county of Cavan which he has surveyed, there are above 90 bogs, no one of which exceeds 500 Irish acres, but which taken collectively contain above 11,000 Irish, which is equivalent to above 17,600 English acres, besides many smaller bogs varying in size from five to twenty acres.

Most of the bogs which lie to the eastward of the Shannon, and which occupy a considerable portion of the King's county and County of Kildare, are generally known by the name of the Bog of Allen: it must not however be supposed that this name is applied

to any one great morass: on the contrary, the bogs to which it is applied are perfectly distinct from each other, often separated by high ridges of dry country, and inclining towards different rivers, as their natural directions for drainage, so intersected by dry and cultivated land, that it may be affirmed generally, there is no spot of these bogs, to the eastward of the Shannon, so much as two Irish miles distant from the upland and cultivated districts.

With this first and general view of the subject, we had no hesitation in selecting at once the whole of the eastern portion of the great district above referred to, as the object of our first inquiries, forming in itself one whole, whose parts had more or less connexion with each other, lying in the centre of Ireland, in the immediate vicinity of some of the richest and best cultivated counties; intersected also by the two great lines of navigation, the Grand and the Royal canals, and presenting in common apprehension very consi, derable obstacles to improvement, the overcoming of which would in itself demonstrate the practicability of the improvement of the bogs of Ireland in most other cases."

The commissioners then proceed to state the particulars of their parcelling out the bogs to be sur veyed, to different engineers, with the pay allotted to them and the persons employed under them; and they then give some observations derived from the first report delivered in, that of Mr. Griffith, to whom was consigned a district forming the eastern end of the bog of Allen, and containing 36,430

English

English acres of bog. Of these we shall transcribe some of the most instructive.

"There are many, we believe, who consider the bogs of Ireland to be low and marshy tracts of country, not very dissimilar in their composition from the fens of Lincolnshire; others, aware that the substance of which they are formed greatly differs from that of the fen districts, attribute nevertheless the origin of both to pretty nearly the same causes; while an opinion, more prevalent, and perhaps not less erroneous than either of the foregoing, attributes their formation to fallen forests, which are supposed at some former period to have covered these districts, and to have been destroyed either by the effects of time, or by hostile armies in the early wars of Ire land.

The facts stated in Mr. Griffith's report are obviously inconsistent with any of these suppositions; the bogs which he has surveyed being every where in elevated situations; and the trees which have hitherto been so constantly found buried in the edges of these bogs, where alone it is probable they have generally been sought for, are very rarely to be found in the interior parts, at least of this district.

Without entering in this report into any inquiry as to the origin of these peat bogs, we are however anxious to give such persons as have not had an opportunity of examining them, some idea of the general appearances which they actually present.

It appears from Mr. Griffith, that each of the four bogs included in the subject of his report, is

a

mass of the peculiar substance called peat, of the average thickness of 25 feet, no where less than 12, nor found to exceed 42; this substance varying materially in its appearance and properties, in proportion to the depth at which it lies; on the upper surface, covered with moss of various species, and to the depth of about ten feet, composed of a mass of the fibres of different vegetables in different stages of decomposition proportioned to their depth from the surface, generally however too open in their texture to be applied to the purposes of fuel: below this, generally lies a light blackish brown turf, containing the fibres of moss still visible, though not perfect, and extending to a further depth of perhaps ten feet under this. In the instance exhibited in the section at the close of Mr. Griffith's report, are found small branches and twigs of alder and birch; but we do not understand him as being of opinion that such is by any means generally the case. At a greater depth the fibres of vegetable matter cease to be visible, the colour of the turf becomes blacker, and the substance much more compact, its properties as fuel more valuable, and gradually increasing in the degree of blackness and compactness proportion. ate to its depth. Near the bottom of the bog it forms a black mass, which when dry has a strong resemblance to pitch, or bituminous coal, and having a conchoidal frac ture in every direction, with a black shining lustre, and suscepti ble of receiving a considerable polish. Immediately below this lower stratum there is generally found a thin stratum of yellow or

blue

blue clay, varying in thickness from one to six feet; in some places the peat rests on a thinner stratum of yellowish white marl, containing upon an average about 60 per cent. of calcarious matter. This stratum of clay in this district universally rests on a solid mass of clay and lime-stone gravel mixed together, and extending to an unknown depth.

We should further consider the peat moss as partaking in its general nature of the property of sponge, completely saturated with water, and giving rise to different streams and rivers for the discharge of the surplus waters which it receives from rain or snow. These streams in this district almost uni. versally have worn their channels through the substance of the bog down to the clay or limestone gravel underneath, dividing the bog into distinct masses, and presenting in themselves the most proper situations for the main drains, and which, with the assistance of art, may be rendered effectual for that purpose.

Such is the internal structure of the bogs in this district.

1

Viewing them externally they present surfaces by no means level, but with planes of inclination amply sufficient for their drainage. The highest summit of any part of the bogs in this district is 298 feet above the level of the sea, taken at an ordinary spring-tide in the bay of Dublin; while the lowest point any where on their surface is 84 feet lower than the highest, and therefore 214 feet above the level of the sea. It requires a mere inspection of the map and sections to be convinced that there is no part of these

bogs from which the water may not be discharged into rivers in their immediate vicinity, and with falls adequate to their drainage; and we observe, in the instance of the bog of Timahoe, that a part of its water is discharged into the sea at Drogheda, and another part below Waterford."

REPORT MADE TO THE INSTI

TUTE, &C. ON WRITING INK. From Annales de Chimie, in the

Philosophical Magazine.

The object proposed by M. Tarry in his memoir is to explain:

1. The processes employed for discharging writing from paper. 2. The processes for reviving writings which have been apparently obliterated.

3. The best way to improve common ink.

4. Finally, the discovery of an ink which should resist all chemical agents.

We shall now give an abridgement of these four articles.

ARTICLE I.

Processes for discharging Writing.

The art of discharging writing is very ancient, and the means employed are very simple. In fact, we know that it is sufficient to moisten a written paper with any acid, when the writing will gradually disappear. But all the acids cannot be employed with equal success. Some leave a stain on the paper, which is not easily removed; others corrode, and render the paper unserviceable. The way to avoid these inconveniences is to make choice of an acid which shall act on the writing only, without

injuring

injuring the paper, or giving it a colour different from that which it had before it was written upon.

In order to discover such of the acids as are best suited for the operation in question, the author determined to submit common writing ink to the action of different acids, and to observe carefully the phænomena which these bodies present at the time of their mixture. According to him, the sul phuric acid easily takes out writing, but at the same time it gives an oily tint to the paper.

The acid oxalate of potash produces more certain and more prompt effects. The oxygenized muriatic acid, if it be newly made, seems to be preferable to the above two acids, because at the same time that it takes out the writing, it bleaches the paper without altering it.

It is not the same case with the nitric acid, which always takes out the ink, but soon penetrates the paper, and forms above it undulated lines of a yellow colour.

We may succeed, however, in softening both these effects, by taking the precaution to dilute the nitric acid with a sufficient quantity of water, or to wash the paper immediately after the writing has been taken out.

A mixture of the muriatic and nitric acids has but a slow actionupon writing. It bleaches the paper, and does not oppose its desic cation, as when we employ the nitric acid alone.

In general, whatever be the kind of acid employed to discharge writing, it is always proper, when the operation is performed, to dip the paper in water, in order to dissolve the new combinations which the

All the methods which have been given for discharging writing consist, as abovementioned, in decomposing the ink, and in forcing its constituent parts to form other combinations. These combinations, being decomposed in their turn by different agents, may regain a tint, which, if it be not that of ink, at least exhibits a shade which becomes perceptible enough for ascertaining the letters and words which had been traced on the paper before it was touched by the acids.

The gallic acid is, according to the author, one of those agents, which in this case succeeds very well.

The liquid prussiate of lime also produces a good effect.,

It is the same case with the alkaline hydrogenated sulphurets. But it is very certain that we never obtain any success from the employment of these agents, when

WC

we have left any acid long in contact with the writing, and particularly if we have washed the paper afterwards.

In short, we may easily conceive, that in this case the constituent parts of the ink which were combined with the acid, and had formed with it compounds soluble in water, having been taken up by this fluid, ought not to leave any trace of their existence longer; and consequently it is impossible that the agents employed for discovering them can render them visible.

It is also for this reason that the gallic acid, the liquid prussiate of lime, the alkaline hydrogenated sulphurets, and so many other reagents which have been so much praised, can no longer be regarded as infallible methods for reviving writing.

ARTICLE III.

Improvement of Common Ink.

.. Most of the inks now in use are of a bad quality. Some are spontaneously destroyed; others im⚫ perceptibly lose their black colour, and assume a yellow one; several, after a length of time, enter into the paper, and spoil it lastly, there are some which are first pale, and then become very black.

All these differences arise from the nature of the substances which have been employed in the making of the ink.

- Convinced of the advantage of having a good article of this kind, the author commenced a series of experiments, but is forced to admit that he has not discovered any recipe superior to that which has been published by Lewis. This

ink, according to our author, combines every advantage: but we must observe, that it is no more exempt than the rest from being dissolved in the acids, and in this respect it has an inconvenience which those who wish to discharge writing from paper know very well how to profit by This circumstance, no doubt, induced M. Tarry to make some new experiments, in order to obtain an ink which should be inalterable by chemical agents; and he appears to us to have succeeded in his object,

ARTICLE IV.

Discovery of an Ink which resists the action of chemical agents.

The author describes his invention in the following words:

My ink is founded upon principles different from those of all others. It contains neither gallnuts, Brazil wood, or Campeachy gum, nor any preparation of iron: it is purely vegetable, resists the action of the most powerful vegetables, the most highly concentrated alkaline solutions, and, finally, all the solvents.

"The nitric acid acts very feebly upon the writing performed with this ink. The oxymuriatic acid makes it assume the colour of pigeons' dung. After the action of this last acid, the caustic alkaline solutions reduce it to the colour of carburet of iron: the characters of the writing nevertheless remain without alteration, and it cannot pass through these different states, except after long macerations. The principles of which it is composed render it incorruptible, and it can retain its properties many years."

The