ply was first practised by a private individual at Paisley. This public spirited adventurer was amply remunerated for his expenditure, and we cannot doubt but that similar speculations on a lar ger scale, if properly conducted, will yield an ample return to the first subscribers. We hope the example which has thus been given will be followed by public spirited individuals in other large towns. Its benefits would soon be felt, and it would yield advantages to the community in general, which cannot be calculated upon." (4 Comm. Mag. 121.)

Sheet Iron. Ordnance. Iron Cables.-In consequence of information requested of me, I have found it necessary to make some enquiries, as to the manufacture of Sheet Iron. The fault of this article when made in this country, is stated to be, that the plates, or sheets, are rough and uneven in consequence of the scales they acquire in the process of heating for the purpose of being rolled. The appearance of the plates is mended, by being annealed of slightly blued, but this is no cure for the evil. My notions on the subject are these.

Every metal, particularly Iron, when exposed to atmospheric air in a red heat, will attract and combine with the oxygen of the atmosphere, and become oxyded. The oxyded iron will either scale off, or remain upon the plate in the form of scales, and make it rough, The cause of the scales and of the roughness of the surface, therefore, is oxyded iron. The cause of the iron becoming oxyded, is that a current of air, not deprived of its oxygen by the coals, comes in contact with the hot iron, and deposits its unconsumed oxygen in the metal.

When a plate of iron is laid upon charcoal for the purpose of being heated previous to its being rolled, the interstices of the charcoal admit more air than the charcoal can consume, or de-oxy. genate that air combines with the under side of the plate, which thereby becomes rough and scaly: the upper side of the plate becomes less so, because the air that passes over it is in part de prived of its oxygen. If there be three plates, the bottom of the undermost will be most oxyded, and then the top of the uppermost. The middle plate will be free from scales: it is heated in the same manner as if it were in a muffle, which is the method of heating the iron intended to be rolled, in some parts of England, and effectually prevents the imperfection complained of.

If, instead of charcoal, a bituminous stone coal is used, the iron plate comes away from the fire much purer and cleaner. The

coals are apt to coak together, and admit no more air through them, than they can decompose: besides which, the smoke of the coal F greatly tends to decompose the current of air which passes immediately under the lowest plate. Coal, therefore, is the best fuel for the purpose; that is, the coal that smokes and flames, while it burns.

But, if the rollers be well greased while the iron is passing through them, which they ought to be, the scales separate, the surface becomes smooth, and a fine bluish colour can be afterward given by proper annealing, if it be necessary to please the eyesight.

While I am upon the subject of iron, I feel much inclined to regret that the Ordnance with which our Navy is supplied, is not better than I hear it is. I do not know the fact, but I am told, that had the guns on board Commodore Rogers's ship been good, he would have taken the Little Belt: and that Commodore Chauncey was nearly killed by the bursting of a cannon; an accident that happens so frequently on board our vessels of war, as to become an evil of great magnitude. About a month ago a general officer in our regular army, told me, that he had seen a lump of lead about five pounds weight taken out of a cannon; the lead had been run in to conceal a defect in the casting. If this be the case, some remedy should be applied.

In England, spring-chains of iron have been substituted instead of Cables. In 1812 three ships of the lie were thus fitted up: whether the improvement, if it be one, is continued, I know not.

Thermometers.-The following formula for the conversion of the degrees of the various Thermometers that are in use in this country, in England, and the continent of Europe, into each other, will be found useful to a chemical and philosophical student. To convert the degrees of Reamur's into those of Fahrenheit's.

RX9

+32=F. 2d. To convert those of Fahrenheit into Reamur's.

4. F-32X4 9

R. 3d. To convert Celsius's into Fah.

4th. To convert Fahrenheit's into Celsius's.

convert Celsius's degrees into Reamur's.

9

F-32×5_C. 5th. To

Thus we may convert the one into the other with the greatest facility, but to such readers as are unacquainted with the algebraic expressions of arithmetical formulæ, it will be necessary to express one or two of them in words, in order that their use may be understood. First, then, To convert the degrees of Reamur's into those of Fahrenheit's: Multiply the degree of Reamur by 9, divide the product by 4, and to the quotient add 32; the sum expresses the corresponding degree on the scale of Fahrenheit. Second, To convert the degrees of Fahrenheit into those of Reamur: From the degrees of Fahrenheit subtract 32, multiply the remainder by 4, and divide the product by 9, the quotient will be the degree according to the scale of Reamur. And so on for the rest.

Poppy Oil. Benni Seed. Ben Nut. At Harmony, half a day's ride from Pittsburgh, (both places objects of very great interest) the settlers, use oil expressed from the poppy seed, exclusively, in lieu of olive oil for sallads, &c. It is nearly, if not quite equally good. This oil is becoming common in Europe as a substitute for olive oil. The poppy seed, may be eaten with impunity when ripe. I do not see why its use should be confined to the settlement of Harmony. The Ben, Bene, or Benni Seed common in the Carolinas, can furnish, as I am informed, oil enough to supply the United States at a cheap rate. I have eaten the oil of the Ben or Behen nut in England, and I find no difference between it, and olive oil. Why should this last be imported? But I doubt whether the Ben or Behen nut be the same with the Benni seed. I suspect this last to be the Sesamum; but I have never seen it. Glans unguentarius, Balenos murepsiki, is the fruit of the Guilandina Moringa. The oil is prepared in the Levant, in Egypt, in Syria, and in Italy, by expression. It is valuable for its purity, and its freedom from smell and taste, and for its property of remaining long without alteration or rancidity, which makes it extremely valuable in pharmaceutical preparations. Rees' Encyclopædia.

The Behen nut,

Madder. A few years ago, I procured from England, and I distributed in Philadelphia some plants of the Smyrna Madder (Lizari) to Mr. Bern. M'Mahon, to Mr. J. Vaughan, to Mr. Jos. Clay, to Mr. Seth Craig. I know not what has been done with them, or whether any of the plants lived. I do not know a more valuable present that could be made to the cotton manufacture of this country. The Turkey red cannot be well dyed with the Dutch, Zealand, or Crop Madder. I mention this in consequence of knowing that the Harmony settlers, raise all their own madder, for

their extensive woollen manufactory, why cannot this be done eve ry where?

English Madder.-Mr. Spencer Smith has lately introduced that valuable plant, Smyrna Madder, into this country. Mr. Smith furnished the society of Arts with some seed, from which Mr. Salisbury, of the Botanical-garden, Sloane street, has raised plants that have grown in the most promising manner; he expects to obtain seed from them, and there is every reason to hope that this useful dye-root will, in a short time, become naturalized to our soil. (3 Comm. Mag. 248.) Query on the Cultivation of Madder, and Observations thereon. To the Editor of the Tradesman, or Commercial Magazine. SIR,-In looking over the list of articles permitted to be im ported to this country from the enemy under his majesty's Orders in Council, and for which it should appear that we stand in great need for the support of our manufactures, I observe the article of madder one, and on referring to the custom house lists of importation, I see that article makes a very conspicuous figure against our balance of trade. As this is an article mostly brought from Holland, it may be inferred that the climate of England would not be unfavourable thereto; and although the great argument is for cultivating every possible spot with the more necessary article of corn, yet there are many unprofitable and considerable spots of ground unoccupied, quite unfavourable to wheat or other corn, that I may presume might be occupied by the cultivation of mad der; I could therefore wish to know if it has been attempted, and with success in this country. If trial has not already been made, it is not too late to attempt it, and at the same time I beg leave to close my question with the following account of the cultivation of that root, for the benefit of those whom it may concern, taken from the French Journal de Physique.

This plant may be propagated either by offsets or seeds; if the latter method is preferred, the seed should be of the true Turkish kind, which is called lizari in the Levant. On a light thin soil the culture cannot be carried on to any degree of profit, that soil in which the plant delights is a rich sandy loam, being three feet or more in depth. The ground being first made smooth is divided into beds four feet wide, with alternate alleys, half a broad again as the beds; the reason of this extraordinary breadth of the alleys will appear presently. In each alley is to be a shal low channel for the convenience of irrigating the whole field, &c

that part of the alley which is not otherwise occupied may be sown with legumes.

"The madder seed is sown broad cast in the proportion of from 25 lbs. to 30 lbs. per acre, about the end of April. In a fortnight or three weeks the young plants begin to appear, and from this time to the month of September, care must be taken to keep the ground well watered and free from weeds; if the plants are examined in autumn they will be found surrounded with small yellow offsets, at the depth of two inches; and early in September the earth from the alleys is to be dug out, and laid over the plants of madder to the heights of two or three feet, with this the first year's operation finishes. The second year's work begins in May, with giving the beds a thorough weeding, and care must be taken to sup ply them with plenty of water during the summer; in September the first crop of seed will be ripe, at which time the stems of the plants may be mown down, and the roots covered a few inches with earth taken as before out of the alleys. The weeding should take place as early as possible in the spring of the third year, and the crop, instead of being left for seed, may be cut three times during summer for green fodder, all kinds of cattle being remarkably fond of it. In October the roots are taken up, the offsets carefully separated and immediately used to form a new plantation, and the roots, after being dried, are sold, either without further preparation, or ground to a coarse powder and sprinkled with an alkaline ley. The roots lose four-fifths of their weight in drying, and the produce of an acre is about two thousand pounds weight of dry saleable madder.

"I need not take up more of your time or place by pointing out the variety of uses this root is of, particularly in various colours for dying, nor pointing out the profit to be derived from a cultiva tion of this root, an acre producing a ton, saleable at more than 1207.; but this would depend upon circumstances and the success of the cultivation.

Your's truly,

Manchester, February, 1810.

K. K.

"Respecting the subject of cultivating Madder in this country, we beg leave to inform our Correspondent, that it has already been. attempted, but of the particulars attending it, or probable result, we are not yet so fully acquainted as to be sanguine in expectation of The result thereof: in page 248, No. 15, Vol. 3. will be seen a noVol. II.

TT