London, Wednesday, June 4, 1851.

Although I have not yet found time for a careful and thorough examination of the machinery and processes recently invented or adopted in Europe for the manufacture of cheap fabrics from Flax, I have seen enough to assure me of their value and importance. I have been disappointed only with regard to machinery for Flax-Dressing, which seems, on a casual inspection, to be far less efficient than the best on our side of the Atlantic, especially that patented of late in Missouri and Kentucky. That in operation in the British Machinery department of the Exhibition does its work faultlessly, except that it turns out the product too slowly. I roughly estimate that our Western machines are at least twice as efficient.

M. Claussen is here, and has kindly explained to me his processes and shown me their products. He is no inventor of Flax-dressing Machinery at all, and claims nothing in that line. In dressing, he adopts and uses the best machines he can find, and I think is destined to receive important aid from American inventions. What he claims is mainly the discovery of a cheap chemical solvent of the Flax fiber, whereby its coarseness and harshness are removed and the fineness and softness of Cotton induced in their stead. This he has accomplished. Some of his Flax-Cotton is scarcely distinguishable from the Sea Island staple, while to other samples he has given the character of Wool very nearly. I can imagine no reason why this Cotton should not be spun and woven as easily as any other. The staple may be rendered of any desired length, though the usual average is about two inches. It is as white as any Cotton, being made so by an easy and cheap bleaching process. M. Claussen's process in lieu of Rotting requires but three hours for its completion. It takes the Flax as it came from the field, only somewhat dryer and with the seed beaten off, and renders it thoroughly fit for breaking. The plant is allowed to ripen before it is harvested, so that the seed is all saved, while the tediousness and injury to the fiber, not to speak of the unwholesomeness, of the old-fashioned Rotting processes are entirely obviated. Where warmth is desirable in the fabrics contemplated, the staple is made to resemble Wool quite closely. Specimens dyed red, blue, yellow, &c., are exhibited, to show how readily and satisfactorily the Flax-Cotton takes any color that may be desired. Beside these lie rolls of Flannels, Feltings, and almost every variety of plain textures, fabricated wholly or in good part from Flax as prepared for Spinning under M. Claussen's patent, proving the adaptation of this fiber to almost every use now subserved by either Cotton or Wool. The mixtures of Cotton and Flax, Flax-Cotton and Wool, are excellent and serviceable fabrics.

The main question still remains to be considered—will it pay? Flax may be grown almost anywhere—two or three crops a year of it in some climates—a crop of it equal to three times the present annual product of Cotton, Flax and Wool all combined could easily be produced even next year. But unless cheaper fabrics, all things considered, can be produced from Flax-Cotton than from the Mississippi staple, this fact is of little worth. On this vital point I must of course rely on testimony, and M. Claussen's is as follows:

He says the Flax-straw, or the ripe, dry plant as it comes from the field, with the seed taken off, may be grown even here for $10 per tun, but he will concede its cost for the present to be $15 per tun, delivered, as it is necessary that liberal inducements shall be given for its extensive cultivation. Six tuns of the straw or flax in the bundle will yield one tun of dressed and clean fiber, the cost of dressing which by his methods, so as to make it Flax Cotton, is $35 per tun. (Our superior Western machinery ought considerably to reduce this.) The total cost of the Flax-Cotton, therefore, will be $125 per tun or six cents per pound, while Flax-straw as it comes from the field is worth $15 per tun; should this come down to $10 per tun, the cost of the fiber will be reduced to $95 per tun, or less than five cents per pound. At that rate, good "field-hands" must be rather slow of sale for Cotton-planting at $1,000 each, or even $700.

Is there any doubt that Flax-straw may be profitably grown in the United States for $15 or even $10 per tun? Consider that Flax has been extensively grown for years, even in our own State, for the seed only, the straw being thrown out to rot and being a positive nuisance to the grower. Now the seed is morally certain to command, for two or three years at least, a higher price than hitherto, because of the increased growth and extended use of the fiber. Let no farmer who has Flax growing be tempted to sell the seed by contract or otherwise for the present; let none be given over to the tender mercies of oil-mills. We shall need all that is grown this year for sowing next Spring, and it is morally certain to bear a high price even this Fall. The sagacious should caution their less watchful neighbors on this point. I shall be disappointed if a bushel of Flax-seed be not worth two bushels of Wheat in most parts of our Country next May.

Our ensuing Agricultural Fairs, State and local, should be improved for the diffusion of knowledge and the attainment of concert and mutual understanding with regard to the Flax-Culture. For the present, at any rate, few farmers can afford or will choose to incur the expense of the heavy machinery required to break and roughly dress their flax, so as to divest it of four-fifths of its bulk and leave the fiber in a state for easy transportation to the central points at which Flax-Cotton machinery may be put in operation. If the Flax-straw has to be hauled fifty or sixty miles over country roads to find a purchaser or breaking-machine, the cost of such transportation will nearly eat up the proceeds. If the farmers of any township can be assured beforehand that suitable machinery will next Summer be put up within a few miles of them, and a market there created for their Flax, its growth will be greatly extended. And if intelligent, energetic, responsible men will now turn their thoughts toward the procuring and setting up of the best Flax-breaking machinery (not for fully dressing but merely for separating the fibre from the bulk of the woody substance it incloses) they may proceed to make contracts with their neighboring farmers for Flax-straw to be delivered in the Autumn of next year on terms highly advantageous to both parties. The Flax thus roughly dressed may be transported even a hundred miles to market at a moderate cost, and there can be no reasonable doubt of its commanding a good price. M. Claussen assures me that he could now buy and profitably use almost any quantity of such Flax if it were to be had. The only reason (he says) why there are not now any number of spindles and looms running on Flax-Cotton is the want of the raw material. (His patent is hardly yet three mouths old.) Taking dressed and hetcheled Flax, worth seven to nine cents per pound, and transforming it into Flax-Cotton while Cotton is no higher than at present, would not pay.

Of course, there will be disappointments, mistakes, unforeseen difficulties, disasters, in Flax-growing and the consequent fabrications hereafter as heretofore. I do not presume that every man who now rushes into Flax will make his fortune; I presume many will incur losses. I counsel and urge the fullest inquiry, the most careful calculations, preliminary to any decisive action. But that such inquiry will lead to very extensive Flax-sowing next year,—to the erection of Flax-breaking machinery at a thousand points where none such have ever yet existed—and ultimately to the firm establishment of new and most important branches of industry, I cannot doubt. Our own country is better situated than any other to take the lead in the Flax-business; her abundance of cheap, fertile soil and of cheap seed, the intelligence of her producers, the general diffusion of water or steam power, and our present superiority in Flax-breaking machinery, all point to this result. It will be unfortunate alike for our credit and our prosperity if we indolently or heedlessly suffer other nations to take the lead in it.

P. S.—M. Claussen has also a Circular Loom in the Exhibition, wherein Bagging, Hosiery, &c., may be woven without a seam or anything like one. This loom may be operated by a very light hand-power (of course, steam or water is cheaper), and it does its work rapidly and faultlessly. I mention this only as proof of his inventive genius, and to corroborate the favorable impression he made on me. I have seen nothing more ingenious in the immense department devoted to British Machinery than this loom.

I understand that overtures have been made to M. Claussen for the purchase of his American patent, but as yet without definite result. This, however, is not material. Whether the patent is sold or held, there will next year be parties ready to buy roughly dressed Flax to work up under it, and it is preparation to grow such Flax that I am urging. I believe nothing more important or more auspicious to our Farming Interest has occurred for years than this discovery by M. Claussen. He made it in Brazil, while engaged in the growth of Cotton. It will not supersede Cotton, but it will render it no longer indispensable by providing a substitute equally cheap, equally serviceable, and which may be grown almost everywhere. This cannot be realized too soon.