and science! The society, to its honour, does not make this work an object of speculation; it merely desires to cover its expenses. It is well convinced, that, to arrive at perfection in the arts, means must be given to all those who exercise them of acquiring instruction easily, and with the least possible expense. To attain this object no sacrifice impedes it; it neither reckons the number of the plates nor the perfection with which they are executed, in order to render the machines more easily understood.

The letter-press contains also much matter, in a pica type. All the pages are full, and the articles succeed one another without any blank.

Description des Machines et Procédes specifiés dans les brevets d'Invention, de Perfectionnement, et d'Importation, dont la durée est expirée: publicé d'apres les ordres du ministre de l'intérieur; par M. CHRISTIAN, directeur du Conservatoire des Arts et Metiers. Paris. Tom. iv. un volume de 348 pages, et 32 planches. Prix 25 francs.-Or, a Description of Machines and Processes specified in breviets of Invention, of Improvement, and of Importation, the duration of which has expired. Published by the order of the minister of the interior, by M. CHRISTIAN, director of the Conservatory of Arts and Trades. Volume the fourth.

THIS work is printed by the order and at the expense of the French government, in consequence of the articles 15 and 16 of the law of the 27th of January, 1791, The 15th article decrees, that at the expiration of every pa tent the discovery or invention shall belong to society at large; that the description of it shall be made public and

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the use of it be permitted throughout the kingdom, in order that every citizen may freely exercise and enjoy it, The 18th article decrees that the description of the discovery declared in the patent shall be, also, in the same way, made public; and the use of the means and processes relative to such discovery shall be also declared free throughout the kingdom, when the patent right shall have expired.

The law imperiously orders that every patent, without exception, shall be published immediately after its expiration, except in particular cases. To the present time, however, it appears that no exception has been declared, and there, therefore, cannot exist any proper reason to justify the suppression of one brevet of the collection.

Three volumes of these patents have been published previously to that of which we now treat. M. Molard, formerly director of the Conservatory of Arts and Trades, superintended the printing of the first volume, which was done in exact conformity to the law. It must be admitted, however, that there are in that volume a great many insignificant patents. But M. Molard well knew that, in the arts, a thing may appear very insignificant which may yet excite in the mind of an artist, having a fertile imagination, ideas which he would not have had till, by these means, the germs had been unfolded; and thus he enriches his country with valuable and new discoveries.

M. Molard took care to add very instructive notes to these patents, whenever he found it necessary. In consequence, the first volume has been sought after with considerable eagerness. M. Christian, on the contrary, in the subsequent volumes which have been printed under his direction, informs us that, besides some sup

pressions which he has judged necessary, he has only pointed out the titles of the patents, the object of which is a chimerical conception which experience has determined, or a thing which every body knows, or which nobody, at the present time, has a desire to know. This is evidently a liberty which he ought not to have taken, and which he is not justified in having taken. To justify, in some sort, this suppression, M. Christian says, that those persons who wish to become acquainted with the patents of which he has only given the titles, may apply to the Conservatory where they are deposited. This excuse is inadmissible. Who is there that does not know the formalities, without number, which beset every one who applies to the Conservatory and other public or private establishments? Besides, the law has ordered the publication, and M. Christian can have no right to garble it.

It appears that in January, 1821, the number of expired patents amounted to 1506. The four volumes, already published, contain only 326; consequently, in following the same method of publication, eleven or twelve volumes more will be required to contain the 1180 patents which remain to be published at the present moment. And if only one be published annually, as has been done for the last three years, we shall not know, in twelve years, the discoveries which we have the right to enjoy in a much shorter time.

To obey the law, and to enable industry to enjoy the riches which belong to it, all the expired patents ought to be published without delay. A number ought to be published every three months of the expired patents, beginning from 1822. Four numbers would form a yearly volume. And of the expired patents, yet in arrear, it ought to be ordered that two volumes should be delivered annually. The only effort required in getting

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out these reports, would be merely to correct, in copying, the errors in language, and to attend, with care, to the plates. In adopting this plan the law would be fulfilled, and the interest of our manufactures and the public prosperity consulted.

It is to be lamented, too, that this volume, when compared with the last work, the Bulletin de La Societie d'Encouragement pour l'Industrie Nationale, is excessively dear. The price is 25 francs. Its pages are much more loosely printed, not containing more than onehalf the letter-press of the Bulletin. The plates, too, cannot be compared with the plates of the last mentioned work.

Hortus Anglicus, or the Modern English Garden, containing a familiar Description of all the Plants which are cultivated in the Climate of Great Britain, either for use or ornament; and of a Selection from the most established Favourites of the Stove and Green-House; arranged according to the system of Linnæus, with remarks on the properties of the most valuable species. By the author of the "British Botanist;" 2 vols. 12mo. pp. 1135.

THIS is a useful work, and will be found extremely convenient to persons desirous of prosecuting the science of Botany in a methodical series. It is to be regretted, however, that the work is printed in two volumes: one octavo would have been much more advantageous for consultation; and a work of this nature is chiefly calculated for such a purpose.

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Polytechnic and Scientific Entelligence.

GREAT BRITAIN.

Royal Society.

THE first part of the Transactions of this Society for 1822 has just been published. It consists of various papers, some of considerable interest and importance. That by the president on the electrical phenomena exhibited in vacuo, proves that the activity of his mind, and his disposition for experimental research, are still unabated.

The papers contained in this part are as follow:

The Bakerian Lecture. An account of Experiments to determine the amount of the Dip of the Magnetic Needle in London, in August, 1821, with remarks on the Instruments employed in such determination. By CAPT. E. SABINE.

"70° 03′ may be considered as the mean dip of the needle towards the north in the Regent's Park, in August and September, 1821, within four hours of noon, being the limit within which all the experiments were made.

In referring to the observations made on this subject by Mr. NAIRNE, in 1772; and Mr. CAVENDISH, in 1776, and comparing their mean amount 72° 25′ in 1774, with the dip in the year above determined, we obtain 3.02 as a mean annual rate of diminution between 1774 and 1821; which is less by two-fifths than the mean annual diminution at Paris, between the years 1798 and 1814, as deduced from the observations of Messrs. HUMBOLDT, GAY LUSSAC, and ARAGO; whence it might be inferred, if sufficient dependance could be