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REPORT MADE TO THE INSTITUTE, more certain and more prompt effects. r. &c. ON WRITING INK. The oxygenized muriatic acid, if it be

newly made, seems to be preferable to . From Annales de Chimie. the above two acids, because at the

same time that it takes out the writing, The object proposed by Mr Tarry it bleaches the paper without altering in his memoir is to explain,

1. The processes employed for dis. It is not the same case with the nicharging writing from paper.

tric acid, which always takes out the 2. The processes for reviving wriink, but soon penetrates the paper, tings which have been apparently ob. and forms above it undulated lines of literated.

; a yellow colour. . 3. The best way to improve com We may succeed, however, in sofa

tening both these effects, by taking 4. Finally, the discovery of an ink the precaution to dilute the nitric acid which should resist all chemical agents. with a sufficient quantity of water, or : We shall now give an abridgment to wash the paper immediately after of these four articles. .

the writing has been taken out.

A mixture of the muriatic and niARTICLE I.

tric acids has but a slow action upon Processes for discharging Writing. writing. It bleaches the paper, and

does not oppose its desiccation, as The art of discharging writing is when we employ the nitric acid alone. very ancient, and the means employed In general, whatever be the kind of are very simple. In fact, we know acid employed to discharge writing, it that it is sufficient to moisten a writ. is always proper, when the operation ten paper with any acid, when the is performed, to dip the paper in water, writing will gradually disappear. But in order to dissolve the new combina. all the acids cannot be employed with tions which the acids have formed with equal success. Some leave a stain on the particles of ink which have been the paper, which is not easily removed; discharged. others corrode, and render the paper Mr Tarry, at the conclusion of this unserviceable. The way to avoid these article, does not fail to observe, that inconveniences is to make choice of an China ink does not act like common acid which shall act on the writing ink with the acids, as its composition only, without injuring the paper, or is quite different from that which we giving it a colour different from that use for writing of all kinds. So far which it had before it was written from the acids attacking China ink, upon.

they make it, on the contrary, of a .. In order to discover such of the deep black : it cannot be discharged acids as are best suited for the ope. therefore without erasing it. ration in question, the author determined to submit common writing ink to

ARTICLE II. the action of different acids, and to observe carefully the phænomena which Processes for ascertaining what Writhese bodies present at the time of their ting has been substituted for some. mixture. According to him, the sul. thing taken out, and Methods of rephuric acid easily takes out writing, viving the Writing which has disapbut at the same time it gives an oily peared. tint to the paper. The acid oxalate of potash produces All the methods which have been

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given for discharging writing consist, destroyed ; others imperceptibly lose as abovementioned, in decomposing their black colour, and assume a yel. the ink, and in forcing its constituent low one; several, after a length of parts to form other combinations. time, enter into the paper and spoil it; These combinations, being decompo- lastly, there are some which are first sed in their turn by different agents, pale, and them become very black. may regain a tint, which, if it be not All these differences arise from the that of ink, at least exhibits a shade nature of the substances which have which becomes perceptible enough for been employed in the making of the ascertaining the letters and words ink. which had been traced on the paper Convinced of the advantage of ha. before it was touched by the acids. ving a good article of this kind, the

The gallic acid is, according to the author commenced a series of experiauthor, one of those agents, which in ments, but is forced to admit that he this case succeeds very well.

has not discovered any recipe superior The liquid prussiate of lime also pro. to that which has been published by duces a good effect.

Lewis. This ink, according to our It is the same case with the alkaline author, combines every advantage; hydrogenated sulphurets. But it is but we must observe, that it is no more very certain that we never obtain any exempt than the rest from being dis. success from the employment of these solved in the acids, and in this respect agents, when we have left any acid it has an inconvenience which those long in contact with the writing, and who wish to discharge writing from particularly if we have washed the pa. paper know very well how to profit per afterwards.

by. This circumstance, no doubt, inIn short, we may easily conceive, duced M. Tarry to make some new that in this case the constituent parts experiments, in order to obtain an ink of the ink which were combined with which should be unalterable by chemi. the acid, and had formed with it com- cal agents; and he appears to us to pounds soluble in water, having been have succeeded in his object. taken up by this fluid, ought not to leave any trace of theirexistence longer; . and consequently it is impossible that

ARTICLE IV. the agents employed for discovering them can render them visible.

Discovery of an Ink which resists the It is also for this reason that the Action of Chemical Agents. gallic acid, the liquid prussiate of lime, the alkaline hydrogenated sulphurets, The author describes his invention and so many other re-agents which in the following words : have been so much praised, can now My ink is founded upon princi. longer be regarded as infallible me. ples different from those of all others. thods for reviving writing.

İt contains neither gallnuts, Brazil wood, Campeachy gum, nor any preparation of iron : it is purely vegetable, resists the action of the most powerful

vegetables, the most highly concentraImprovement of Common Ink. ted alkaline solutions, and, finally, all

the solvents. - Most of the inks now in use are of “The nitric acid acts very feebly a bad quality. Some are spontaneously upon the writing performed with this

ARTICLE III.

ink. The oxymuriatic acid makes it that in rendering its cultivation and assume the colour of pigeons' dung. preparation better known and underAfter the action of this last acid, the stood, it may be greatly beneficial to caustic alkaline solutions reduce it to the nation. the colour of carburet of iron : the I have the honour to be a member characters of the writing nevertheless of the Bath and West of England remain without alteration, and it can. Agricultural Society, where many not pass through these different states, noble and exalted characters unite their except after long macerations. The talents to promote the public benefit. principles of which it is composed ren- And to one of its earliest and most der it incorruptable, and it can retain respectable members I presume to adits properties many years."

dress this information. The results which we obtained coin. I have been many years a consideracided entirely with those of the author, ble consumer of woad, and have also and we have so hesitation in saying, cultivated it with much success : and that his is the best we have ever seen though I am well experienced in the of the kind which is called indelible usual method of its preparation, I was ink. It is liable, however, to deposit induced to depart from it in consea sediment, a disadvantage which we quence of the great waste of its juices think might be removed by M. Tarry in the old method of grinding and after a few experiments. We have balling. But I shall endeavour to tried to discharge it with all the known give instructions for carrying on each chemical agents, but without effect; process, and leave those who shall un. and we think the inventor deserves dertake it to proceed as they think the thanks of the Institute, and of the best. community at large.

· This plant is cultivated in different parts of England for the use of the

dyers, as well as in France, Germany, ON THE CULTIVATION AND MANU- &c. It is best to sow the seeds in the

FACTURE OF WOAD, AND ITS BE- month of March, or early in April, if

NEFICIAL Use COMBINED WITH In the season invite, and the soil be in • DIGO. By Mr John Parrish. condition to receive it ; but it requires

a deep loamy soil, and is better still From the Bath and West of England with a clay bottom, such as is not sub- Agricultural Society's Papers. ject to become dry too quickly.

It must never be flooded, but situaWoad is a plant which, combined ted so as to drain its surface, that it with indigo, gives the best and most may not be poisoned by any water stagpermanent blue dye hitherto discovered. nant upon it. It is of great importance to our com- If (at any reasonable price) mea. merce, as well as to agriculture, be dow land to break the turf can be ob. ing in nature one of the best preparers tained, it will be doubly productive. of land for a corn crop that has hitherto This land is generally freest from weeds been discovered ; and, if the land is and putrid matter, though sometimes properly chosen for it, and well mana. it abounds with botts, grubs, and snails. ged, will be found very profitable, However, it saves much expence in more particularly at this time, when its weeding ; and judicious management price is advanced to almost an unpre- will get rid of these otherwise destruc. cedented degree: therefore I conceive, tive vermin.. A season of warm shor.. ers, not too dry or too wet, gives the These plants are frequently destroy. most regular crop, and produces the ed in the germination by flies, or anibest woad.

malculæ, and by grubs, snails, &c. as If woad is sown on corn-land, much before observed ; and in order to preexpence generally attends hoeing and serve them, I have steeped the seeds weeding : and here it will require with good success in lime and soot, strong manure, though on leys it is until they began to vegetate ; first seldom much necessary, yet land can- throwing half a load or more of flour not be too rich for woad. On rich lime* on the acre, and harrowing it in. land dung should be avoided, particu. Then plant the seeds as soon as they larly on leys, to avoid weeds. Some break the pod, taking care not to people sow it as grain, and harrow it, have more than one day's seed ready ; in, and afterwards hoe it as turnips, for it is better to be too early, than leaving the plants at a distance in pro- to have their vegetation too strong beportion to the strength of the land : fore it is planted, lest they should re. others sow it in ranks by adrill.plough; ceive injury ; yet I have never observed and some dibble it in, (in quincunx any injury in mine from this, though form, by a stick with a peg crossways, I have often seen the shoot strong. about two or two and a half inches Either harrows or rollers will close the from the point, according to the land,) holes. If the ground be moist it will putting three or four seeds in a hole, appear in a few days; but it will be and these, holes to be from twenty safe, and a benefit to the land, to throw inches to two feet apart, according to more lime on the surface, when, if the richness of the land ; for good showers invite snails and grubs to eat land, if room be given, will produce it, they will be destroyed, which I have very luxuriant plants in good seasons; several times found; particularly once, but if too nearly planted, so that air when the leaves were two inches long, cannot circulate, they do not thrive so and in drills very thick and strong, but well: attention to this is necessary in the ground was dry. When a warm every way of sowing it. I have been rain fell, in less than two hours I found most successful in this last process. the ranks on one side attacked by these Woad very often fails in its crop, from vermin, and eaten entirely off by a large the land not being in condition, or for black grub, thousands of which were want of knowing how to destroy the on the leaves, and they cleared as they botts, snails, wire-worms, &c. that so went, not going on until they had de. often prey upon and destroy it, as well stroyed every leaf where they fixed. as from inattention to weeding, &c. They had eaten six or seven ranks beCrops fail also from being sown on fore I was called by one of my people land that is naturally too dry, and in to observe it. Having plenty of lime, a dry season ; but as the roots take a I immediately ordered it in flour to perpendicular direction, and run deep, be strewed along those ranks which such land as I have described (with were not begun. This destroyed them proper attention to my observations) in vast numbers, and secured the rewill seldom fail of a crop: and if the mainder. Another time, having had season will admit sowing early enough two succeeding crops on four acres of to have the plants strong before the dry land, I considered it imprudent to venand hot weather comes on, there will be ture another. However, as the land almost a certainty of a great produce. after this appeared so clean and rich, ** If the seeds are not sown within a day after the time, it will lose much effect.

I again ventured, but soon found my succeeded at last; but I kept the other error. On examining the roots (for three and four years, when I found it after it had begun to vegetate strong, more steady in its fermentation ; but it was observed to decay and wither still it required a double quantity, and I found thousands of the wire-worm even then its effect was not like that at them, entwined in every root. I from good woad. immediately strewed lime, (four loads, At this time several dyers experiof six quarters each, on the four acres,) enced much difficulty, and one of emiand harrowed it ; when rain coming nence in the blue-trade suffered so on soon after, washed it in, and de- much by woad of his own growth, that stroyed them all, and gave me an exhe declared his resolution to decline traordinary crop; but the first sown the trade altogether. When I pointside of the field, where they had begun, ed out to him that it was the woad never quite recovered like the rest. that occasioned his bad blues, and that And I am fully satisfied, that when I had from the same defect purchased the grub is seen in wheat, &c. the such other woad as would do, and insame treatment (if the weather suited) formed him where he could get it, would destroy them all, as well as he succeeded as usual. His own he change the nature of the land. I need disposed of to a drysalter, who sold it not enter on the wide and extensive again somewhere in the country; and field of observations on the causes of it occasioned such a cause of complaint, weeds, grubs, &c. (which so often as I believe rendered the claim of pay. counteract the labours of the husband- ment to be given up, or partly so: of man,) that occur so differently in dif- `this I am not certain, having it only ferent seasons, and after different treat- from report. I mention this in order ment and improper crops,--further to give those who wish to become growthan to observe that when your land ers of woad, such information as may has not a proper change, then it is that properly direct them. these are experienced in a more de. The leaves of woad on good land in structive degree.

a good season grow very large and Further, it is in vain to expect a long, and when they are ripe show near good crop of woad, of a good quality, their end a brownish spot inclining to from poor and shallow land. The a purple towards its centre, while difference of produce and its value is other parts of the leaves appear green, so great, that no one of any experience but just beginning to turn of a more will waste his labour and attention on yellowish shade; and then they must such lands upon so uncertain a pro- be gathered, or they will be injured. duce. Warm and moist seasons in Woad is to be gathered from twice crease the quantity every where, but to four and even five times in the sea. they can never give the principle which son, as I once experienced (it was an only good land affords.

early and a late season), and for the · In very wet seasons, woad from next spring I saved an acre for seed, poor land is of very little value. I of which I had a fair crop. I picked once had occasion to purchase at such 'the young seedling sprouts off the rest, a time, and found that there was no and mixed with my first gathering of possibility of regulating my vats in what was newly sown ; this was very their fermentation ; and I was under good. During one season I let these the necessity of making every possi- shoots grow too long; the consequence ble effort to obtain some that was the was, that the fibrous parts became produce of a more genial season. I like so many sticks, and afforded no

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