nished, and the information afforded, has been advantageous both to patentees and to the public. The Institute receives nearly all the Journals published in Great Britain and France, devoted to the mechanic arts, and in the analectic department of the Journal will be found all the articles from these publications that can be interesting to the American mechanic or manufacturer. This Journal, thus containing selections of all the most important articles from the foreign publications, and in addition a valuable fund of original information that cannot be elsewhere obtained, it must be evident, possesses for the American mechanic a degree of interest superior to that of any other publication, and that it is absolutely necessary that all should have it who desire to be kept acquainted with the improvements constantly making in the arts.

In addition to the articles upon the subjects immediately embraced in its title, biographical memoirs of persons who have distinguished themselves by useful discoveries appertaining to the Mechanical and Chemical arts, or who have acquired a high degree of reputation by their labours in these departments, will occasionally appear. More frequent notices will also be given of publications intended to promote a general knowledge of the principles of science, or in any way to advance the interests of the operative classes of society.

CONDITIONS.

The Journal is published monthly, each number containing 72 pages, which form two volumes annually, of 482 pages each. Engravings on copper, and on wood, accompany those subjects which require them.

Subscription $5 per annum, payable on the delivery of the sixth number. The work will not be forwarded to subscribers who are one year in arrears. This regulation will, hereafter, be rigidly enforced.

THE FOLLOWING PERSONS ARE AGENTS FOR THE WORK.

Communications for the work may be sent either to the Editor at Washington City, or to the Actuary of the Franklin Institute, Philadelphia: the postage upon them must be paid.

Subscribers sending the amount of their subscriptions by mail, will not be required to pay the postage.

The postage of each number, for any distance not exceeding 100 miles, will be 7 cents, for any greater distance, 12 cents.

PREFACE.

SINCE the publication of the last volume of the Franklin Journal, a material change has taken place in the tenure of the work, and in the scene of the Editor's labours; both of which changes are likely to enhance its value. It was originally issued under the patronage of the Franklin Institute, and it is indebted for many of its subscribers to the exertions of some of the individual members of that body; the whole weight of its fiscal concerns, however, as well as of the literary department, rested upon the Editor. In the present arrangement, he has no concern whatever in the management of it, apart from his duties as Editor, it being now essentially the Journal of the Institute. An Actuary has been appointed, who transacts, at the Hall, all business relating to the distribution of, and subscription for the work. A large, and justly influential body, has thus become identified in its interests, with the success of the Journal, whilst the Editor is relieved from a very irksome part of the concern; and one which was indeed, in some measure, incompatible with the complete performance of his duties, as such. The work has drawn largely upon his funds, and has not yet repaid to him the amount of his actual expenditures; still he has enjoyed, what will ever be to him the most valued portion of his reward, the approbation of the intelligent, and the conviction that he was doing good, by diffusing the principles of science, and correct practical information, among the artizans and manufacturers of our country; a class of our fellow-citizens whose importance we are only beginning to appreciate correctly.

It has already become known to the patrons of the work, that the direction of the National Patent Office has been committed to the Editor. His induction into this station has been such as to afford him unalloyed pleasure, as his appointment has been made without the slightest reference to political considerations, and has been universally approbated. Whilst this station will enlarge the sphere of his usefulness, by putting into frequent requisition, that information upon the practical application of mechanical and chemical science, which it has been the labour of his life to obtain, it will also enable him, through the medium of the Journal, to lay open those stores of the genius and skill of our country men, which, although existing in the Patent Office, have hitherto been but very partially known. The succeeding volume of the Journal will, in consequence, undergo a slight

alteration in its title, by the addition of the words, "and the recording of American, and other patent inventions."

Those persons who examine the English and other periodicals devoted to science and the arts, need not to be informed that numerous articles from the Franklin Journal have been republished in them with distinguished approbation; their conductors having been, generally, just in crediting, and liberal in awarding the meed of praise for our labours. The Editor is not aware that an inordinate share of vanity is one of his characteristics; he, however, feels that "the universal passion" is a powerful stimulant, and that the reward at which he aims has not decreased in its influence, with the increase of his years. After this, need it be said that he was gratified by the following remarks, which appeared in the preface to the last volume of the Register of Arts, published in London? "The major part of the matter introduced consists of original descriptions by the editor; the remainder are the contributions of intelligent correspondents, together with selections from contemporary journals, the most prominent of which is the Franklin Journal of Philadelphia, a work of singular excellence, and unrivalled in utility. To the learned editor of that work, and to our correspondents generally, we therefore gratefully make our acknowledgments for their valuable assistance."

Washington City, June 1st, 1828.

2

Description of an Improved Apparatus for Evaporation and Distilla tion, which is also applicable to several other purposes, such as the concentration of saline liquids, the generation of steam, the manufacture of Vinegar, Verdigris, &c.

In the fifth number of the last volume we gave a description of some recent improvements in the distilling apparatus, and intended to have continued the same subject in the succeeding number, but were compelled to postpone it until the present period. The nature of the revenue laws of Great Britain, as relates to distillation, and various other important considerations, has led to numerous attempts to accelerate this process, some of which have been eminently successful. This subject is evidently connected with various efforts which have been made to improve the steam engine, as a main object in each, is the production of vapour, by means of fire. In many of the patents which have been obtained for improved modes of generating steam, the application of the same apparatus to the purpose of distillation has been pointed out; whilst in others, which were primarily intended to be applied to distillation, it has been proposed to use them also as boilers for steam engines.

The apparatus which we are about to describe, appears, from the letter of its inventor, not to have been subjected to the test of experiment, but to be a new proposition, submitted to the judgment of those who are acquainted with the subject. We perceive some practical objections to its use in certain of the ways designated, but think it worth presenting to our readers; for should it be, like most novel propositions, imperfect, it may yet suffice to suggest useful ideas to others.

The gentleman who proposes the plan, after making some remarks upon the known effect of increasing the surface in promoting evaporation, states that he was most forcibly struck with the rapidity with which the moisture from a wet towel was converted into steam, on holding it before a common fire, and says,

"I then thought that the towel afforded a hint for the construction of a steam generating apparatus, and that absorbent, porous materials, would be the best for the purpose, if they could be arranged conveniently, and were good conductors of caloric. Since then, it appeared to me that I might adopt metal, and apply a very extended surface for the generation of vapour, in a manner more convenient, than the close boiler; and with vastly greater effect, however shallow that boiler might be made.

"Having determined upon the form of my vessel, or rather machine, for the production of vapour, I next considered of a plan for its rapid condensation, in which I flatter myself I have been equally successful, notwithstanding it possesses much less novelty in its arrangements, than the former.

"I shall now describe my apparatus, with reference to the drawing, and at the same time show its application to distillation; and afterwards explain its adaptation to other purposes, namely, for evaporating