author soon condescends to be useful; and has described, with equal simplicity and clearness, his various machines, and the application of the gaseous oxygenated acid, to every different use for which it appears adapted. The employment of the acid in the form of gas is undoubtedly an improvement of the first magnitude and importance; and the very extensive application which it admits in this form renders it an object of the greatest value. The labour of many months is now reduced to a few hours. We shall transcribe what he remarks on the recovery of books and prints grown yellow by age. transcribing the process of M. Chaptal, he adds:

After

• MM. Vialard and Heudier have applied this method to some of the most valuable books of the national library. I believe they were the first who, since the publication of M. Chaptal's memoirs, have employed it with very obvious advantage. In reality, these memoirs show that a great precision in the proportions of the acid must be accompanied by an address in managing the process, very difficult to attain. Without these we may destroy the works that we wish to restore. Engravings and drawings with three crayons may be revivified completely in this way: engravings grown yellow by time are perfectly whitened, and receive a second existence. The traces of age disappear, and the books-thanks to this restorative art!— recover the vigor, the brilliancy, the freshness, which they at first possessed; and, for the first moment in this department, Time finds himself obliged to begin again the destruction with which he had marked his progress."

Art de peindre et d'imprimer les Toiles, &c. Art of painting and printing Linens, of the different Colours distinguished by the Terms great and little Tint. 8vo.-This little work aims only at utility; but the processes are clearly explained; and much inconvenience will be avoided by attending to the directions here given.

We find the necessary instructions for the preparation of cloths; some information respecting the original materials and their properties; on the choice and composition of colours; on the structure and engraving of the plates. It is a useful inanual, and contains the result of observations made in the most respectable manufactories: indeed it appears to contain whatever may be necessary to conduct a similar institution.

Mélanges Physico-mathématiques, &c. A Collection of Memoirs, containing a Description of many new Machines and Insiruments of Philosophy and domestic Economy. By J. B. Berard. 8vo. Paris. This collection is published by order of the minister of the interior, and contains an account of many new and curious machines. We particularly noticed a very

ingenious photometer and manometer, and a nocturlabe, designed to show the hour of the night by the stars. It is useless, however, to enumerate the different objects described (which are eleven in number), as we cannot convey an accurate idea of the machines without the plates. The author supposes his reader to have attained the first principles of geometry and mechanics; and with these assistances the machines will be easily understood.

Histoire Céleste Françoise, &c. French Celestial Hiftory, containing Observations made by many French Astronomers. Published by J. de Lalande. Vol. I. 4to.-This work is in imitation of Flamstead's, whose catalogue has been greatly augmented, and whose errors have been corrected by Herschel. The observations of the Academy of Sciences began in 1666, and were continued to 1685. These were published in 1741 by P. Lemonnier, in his Celestial History. J. D. Cassini designed to publish the continuation, and gave a part of it, in the Memoirs of the Academy, as a part of the article which contained his own observations from 1785 to 1791. M. de Lalande engaged to publish the others, among which there werc several peculiarly exact and important.

In 1796, government ordered the publication of a new celestial history; and M. de Lalande, to whose care it was consigned, chose to begin with the most recent observations, and particularly with those of the stars, which are of most importance to astronomy; for which the world is chiefly indebted to 'his diligence. The observations on eclipses, conjunctions, and oppositions of the planets, as well as those on Mercury, by M. Vidal, occur in the different volumes of the Connoissance des Temps, and for this reason are not inserted in the present history.

The author first gives the observations in the military school, at a period of the revolution when none were made at the great observatory, from a want of astronomers and instruments. We cannot, in this part of our journal, enlarge on the historical details of the successive progress of astronomy in France; and these details, interesting in themselves, are however more so by the proofs they furnish of the extent of the author's knowledge, his indefatigable zeal for the perfection of the science to which his studies are consecrated, and which he has enriched by his discoveries. We shall only add the observations of some other astronomers in the volume before us.

Antony Darquier published in 1777 and 1782 two volumes of Observations, with three continuations, in the Memoirs of the Academy of Toulouse. The third volume appeared in 1792. We here find the sixth continuation of these observations, made at Toulouse in the years 1797 and 1798.

At the end of these Observations we find those of the stars, made in 1783 by J. L. Dagelet, anterior to those of the astronomers who have published in the Memoirs of the Academy for 1789 and 1790. To this volume the author has joined the representation of his great quadrant, and of the machine contrived to move it from the east to the west side of the wall; as well as a figure of the mechanism, contrived by Mechain in the mural of the observatory, to support the centre of the weight of the telescope.

Mappemonde Céleste, &c. Map of the Heavens, or an Explanation of Astronomical Principles, relative to the Terrestrial Globe, and to a general Knowledge of the Heavenly Bodies; with the Application of these two Objects to different elementary Notions of Geometry, Optics, Perspective, and Calculus. By 7. Ch. Maclot. 8vo. Paris.-The author's object was to give a general idea of geometry, so far as it regards the earth and the heavenly bodies. The first part of his work contains an explanation of the map of the world, the phænomena observable at sea, and an explanation of the doctrine of the sphere.

In the second part we find a general table of the principal groupes of stars, and the use of the celestial artificial globe in discovering and distinguishing them.

The supplement is preceded by a short historical account of the origin and progress of astronomy. We next find a general view of geometry, with some new examples of geometrical demonstrations; and the work is concluded by an enumeration of the principles which are the foundation of the numerical calculus, and the use of this calculus in practical geometry..

Voyages au Mont Perdu, &c. Journeys to Mont Perdu, and to the adjacent Parts of the Higher Pyrenees. By L. Ramond. 8vo. Paris.-Though we cannot expect to meet with the deep researches and just taste of M. de la Saussure in similar Alpine tours, yet our author is no unworthy successor of that traveler and naturalist. Of his talents in this department he has given some favourable specimens in different scientific collections; and we have read the present work with great satisfaction and instruction. Our account of it has been delayed, because, had our limits perinitted, it would have been more extensive.

These journeys are divided into four parts. The first two contain the description of two new philosophic and mineralogic tours to Mont Perdu, the most elevated of the Pyrenees. The third part contains a tour to the valley of Gavarnie, and some of the most interesting spots in the neighbourhood, particularly to the port of Canau and to Troumousse. The fourth

is an account of a journey to Vignemale, to Piméné, and to the circus of Gavarnie. The descriptions are concluded by some reflexions on the northern part of the Pyrenean chain. M. Ramond compares the Pyrenees to the Alps; and concludes-1. that the former chain is more simple; 2. that more difficulty seems to have occurred in the formation of the secondary mountains, superimposed on the primitive; 3. that the calcareous substance, both in the primary and secondary mountains, is in greater proportion; 4. that the secondary portion is raised to a more considerable height; and 5. that the invasion is effected in a contrary direction. On the whole, he thinks that the long chain of the Pyrenees presents the most simple order in which mountains may be studied; and that the chain of the Alps multiplies and corrects the data which have formed the bases of theories.

.. GERMANY.

Allgemeine Beitrage zur Befærderung des Ackerbaues, &c. A Collection of Memoirs concerning Agriculture, Arts, Manufac tures, and Professions. Published by 7. G. Geissler. Svo. With Plates. Volume I. Zittau. We hasten to announce this collection, because it appears likely to become a valuable one. Industry, either as it regards agriculture or manufactures, is the source of the prosperity of a state. It is perfected by instruction, and expanded by emulation. To collect every interesting discovery will therefore not only add to the stock of information, but will assist the spread of emulation.

The memoirs are either originally German, or translated from other languages. Eleven are contained in the volume before us. We shall give some account of those which are most interesting, and which can be rendered intelligible without the plates.

I. A Description of a new 'Wheel to spin Flax, with a progressive Spindle; by J. G. Prasse.'

II. On the Danger of employing Vessels of Lead, of Brass, or Copper, in Dairies; by T. Hayes.'

III. A new Method of tanning Leather, and rendering different animal and vegetable Substances impermeable to Water; such as Flax, Hemp, Cotton, Silk, Hair, Wool, &c.; by Desmond.'

IV. A Method of preparing, with Shreds of Leather, a Varnish for the Ornament of Carriages, to varnish Vases, Books, Paper, &c.; by Hooper:'This seems to be an English essay; but we do not recollect to have seen it before. The shreds of leather are reduced to a paste, from which the water is pressed. About a fourth part of hemp, old cordage, &c. with some fine clay, are added to make brown paper, and about three fourths of rags to produce white paper.

V. A Process for obtaining from Charcoal of Wood a larger Proportion of Pot-ash; by G. Glenny.'

VI. A Method of depriving Treacle of its disagreeable Taste, and rendering it a Substitute for Sugar.'-This depends on mixing equal parts of treacle and water, with one-fourth of charcoal; we mean a quarter part of the two substances mixed together. The mixture is to be boiled half an hour, filtered, and evaporated to the consistence of a syrup. As much syrup is thus obtained as was originally employed of treacle.

VII. The Composition of a Water for destroying Caterpillars, Ants, and other Insects; by Tatin.'-A pound and threequarters of black soap is added to as much sulphur, with two pounds of the lycoperdon tuber, and fifteen gallons of water. The whole is mixed and sprinkled on the trees. It is immediately fatal to the insects.

VIII. On the Influence of Vital Air on the Colour of Substances, and on a new Method of preparing solid Pigments for Painters; by Fourcroy.'-This memoir we have had occasion to

notice.

• IX. A horizontal Churn' (much too complicated); ‘by Velley."

X. On the Use of Mordants in dying Cotton red; by Chaptal.'

XI. An Essay on the Means of rendering Pigments more perfect; by Guyton.”

7. Hedwig Species Muscorum Frondosorum, &c. Hedwig's Species of leafy Mosses, illustrated by 77 coloured Copperplates; edited as a posthumous work by Fr. Schwægriehen. 4to. Leipsic. -The name of Hedwig is by no means new to our journal; and we have followed him with care in his minute observations on the fructifications of mosses. We learn, with regret, that he is no more. The present work was only half completed at his death; but the materials have been taken up by his friend and pupil M. Schwægriehen, who has added many very accurate descriptions of specific differences, and, in this work at least, has fulfilled all Hedwig's designs.

The great principle of this author's system is founded on the form of the overture of the capsule; and the secondary principle rests on the form and situation of the flowers. We must not, however, conceal that this arrangement is not universally approved: on the contrary, it has been opposed by many learned botanists, particularly by M. Wildenow. There is undoubtedly much uncertainty in this foundation; but it would not be easy to discover in these plants a more secure basis. Hedwig was well aware of this uncertainty, and has not concealed the inconvenience of his system. He knew that the form of the flowers was subject to variations, and he was no longer willing to separate