which have been introduced within these ten years into French agriculture; and a particular memoir on the dahlia, a plant newly spread over our gardens. Its flower constitutes a fine ornament, and its roots are larger, and almost as good for food as those of the potatoe.

Among the buds of trees there are some which do not spread out with the others, and which are called dead eyes, but which should rather be called sleeping eyes; for they may be brought out of that lethargy even after it has continued for several years. It is generally owing to the tendency of the sap to go to the superior buds, and to elongate them into great branches. The lower buds by this means are deprived of the nourishing fluid. This is no inconvenience in the trees destined merely to produce wood or to furnish shade. But in fruit-trees in which we wish to dispose of the branches in a certain order, we are sometimes obliged to put grafts in the places which the dead eyes occupy, a method both tedious and uncertain. M. Marion de la Martiniere has practised a simpler and more successful method. It is to make a small cut above the dead eye in form of a V reversed, and as deep as the alburnum. By thus stopping the progress of the ascending sap, it is obliged to develope the bud, or to produce others.

We may likewise reckon among the labours of the Class in agriculture the memoirs on the Spanish sheep called merinos, by MM: Tessier and Yvard; the description of the practical school of agri'culture, by M. Thouin; and the essay of a rural code, by M. de la Bergerie, correspondent. But as these books have been published for several months, it is only necessary to mention their titles.

A contrary reason induces us to make some observations on a considerable work which M. de Lasteyrie du Saillant has presented to the Class, on all the branches of agriculture, and of the rural and domestic economy of the Chinese. It is collected from all the authors who have written on China, and embellished by a great number of figures drawn in China, and by Chinese, in which are represented all the proceedings of their industry, and all the instru ments which they employ. This great empire, in which an immense population is entirely supported by agriculture, and in which this art has been uninterruptedly honoured and protected since the first establishment of the monarchy, cannot but have made great progress in it and in fact M. de Lasteyrie makes us acquainted with different instruments, more simple and commodious than those which we employ for the same purposes, and points out to us processes which might be advantageously followed here, principally in the culture of fruit-trees. We might even imitate the Chinese in their dyeing processes. Thus they prepare a blue with some species of renouées, very common here, which, if adopted by us, might diminish the consumption of indigo.

M. Yvard, become lately an associate, had presented while a correspondent a large treatise on the plants injurious to corn, and on the method of keeping cultivated land free from them. What

are usually called weeds, are children of nature, wild plants whose territory is daily invaded by cultivated plants, but which endeavour by all the means in their power to maintain their ground. They soon recover their soil if man neglect them. The wind, water, and animals, transport their seeds; the earth conceals them for a long time, and they vegetate when the favourable moment comes. The imprudent farmer often sows them himself in the manure which he lays on the fields. M. Yvard, who mentions more than 300 species, describes all the care and all the stratagems which must be employed in the kind of war which the farmer must carry on against them, and he treats his subject from actual experience.

This skilful farmer has done a still greater favour to agriculture by publishing last spring, through the medium of the journals, the methods which his experience has suggested as the most proper to repair the losses occasioned by the events of war among the corn and the grass. He has had the happiness to see his counsels fructify. It could not be perceived by the price of corn that our finest provinces have been the fields of battle. It is by such applications of agriculture and art, perfected by the spirit of the sciences, that France has for twenty years contended with the disasters always renewed of a cruel war, and that she has been able to bear without sinking the painful operation on which depended the end of her ills. (To be continued.)

ARTICLE XI.

.1 SCIENTIFIC INTELLIGENCE; AND NOTICES OF SUBJECTS CONNECTED WITH SCIENCE.

I. Lectures.

A Course of Lectures on the Elements of Electrical Science, comprehending Galvanism and Electro-Chemistry, will be commenced by Mr. Singer, on Monday, Nov. 6, at No. 3, Princesstreet, Cavendish-square.d

T

II. Largest Diamond.

The largest diamond hitherto found is in the possession of the Rajah of Mattan, in the Island of Borneo, in which island it was found about 80 years ago. It is shaped like an egg, with an indented hollow near the smaller end. It is said to be of the finest water. It weighs 367 carats. Now as 156 carats are equal to 1 oz. Troy, it is obvious that this diamond weighs 2 oz. 169.87 gr. Troy. Many years ago the Governor of Batavia tried to purchase this diamond. He sent a Mr. Stuvart to the Rajah, who offered 150,000 dollars, two large war brigs with their guns and ammunition, together with a certain number of great guns, and a quantity of powder

and shot. The Rajah, however, refused to deprive his family of so valuable an hereditary possession, to which the Malays attach the miraculous power of curing all kinds of diseases, by means of the water in which it is dipped, and with which they imagine that the fortune of the family is connected.-See Dr. Leyden's account of Borneo, in the seventh volume of the Transactions of the Batavian Society.

III. Voyage of Discovery to Africa.

The gentlemen appointed by Government to prosecute the discoveries of the late unfortunate Mungo Park have at last sailed from England for the coast of Africa. They are Major John Peddie, Capt. T. Campbell, and Mr. Cowdery, staff surgeon. They are said to be very well qualified for the task which they have undertaken. They are to be attended by a company of Negroes. The object of the expedition is to trace the Niger from the place at which Mungo Park left it to the sea, and to determine whether or not it be the same with the Zayr.

IV. Death of Gehlen.

Adolph Ferdinand Gehlen, whose name has occurred repeatedly in the Annals, died at Munich last summer; or perhaps it would be more proper to say that he destroyed himself, since he persisted in a set of experiments in which he was daily exposed to the fumes of arsenic, though warned by his friends of the fatal consequences that would ensue. He became first generally known to the chemical world in 1803 by the publication of a new monthly chemical work, which he entitled, Neues Allgemeines Journal der Chemie (New Universal Journal of Chemistry). Of this journal he published six volumes, which contain a great deal of valuable and original matter. In 1806 he changed the title to Journal fur die Chemie und Physik (Journal of Chemistry and Natural Philosophy). About this time he was chosen a Fellow of the Academy of Sciences of Munich, to which capital he repaired. Yet he still continued to publish his journal at Berlin. But it was infinitely inferior to what it had been, consisting chiefly of translations from foreign journals, and of long papers by Ritter, often highly absurd and ridiculous. He continued it, however, till 1810, when he stopped: no doubt because the sale had diminished so much as not to be equivalent to the expenses of the publication. His principal discovery was the mode of precipitating red oxide of iron by succinate of soda or of ammonia. This discovery has been of considerable use in the chemical analysis of minerals.

V. Confirmation of Mr. Rose's Discovery of the Absence of Urea from the Urine in Hepatitis: being an Extract of a Letter from Dr. Henry, of Manchester.

Soon after the publication of Mr. Rose's paper, in your number for June, a medical friend (Dr. Holme) gave me a specimen of the

urine of one of his patients, a female labouring under chronic hepatitis. He had been struck with the absence of most of the usual qualities of that fluid, such as colour and smell, of both which it was nearly destitute. I found its specific gravity to be only 1'0033 (the average of healthy urine being 1'0200); and its solid contents, not perfectly dried, did not exceed 25 grs. from the wine pint. Finding that no precipitate was occasioned by adding nitric acid to the extract dissolved in a little water, I tried to discover urea in another portion of the same urine by the more accurate test, which I have proposed, of distillation. The distilled fluid very slowly restored the colour of reddening litmus paper, but did not precipitate muriate of lime. It could, therefore, have contained nothing more than a mere trace of carbonate of ammonia, which is always abundantly produced by the distillation of natural urine. As the patient recovered, the urea was very gradually and slowly restored to the urine. These experiments confirm the curious discovery of Mr. Rose; to which it may be added, that the urine of Dr. Holme's patient did not contain an appreciable quantity of uric acid. I was sorry that other engagements interfered at the time, and prevented me from determining exactly the nature of its other contents.

An opportunity lately occurred to me of ascertaining precisely the proportion of urea in the urine of a patient labouring under diabetes mellitus in its most perfect form, before the disease was influenced either by diet or medicines. A wine pint gave 651 grains of solid extract; and of this only 16 grs., or part, were urea. No urea could be discovered by the action of nitric acid. The processes employed in detecting it were those which I have described in the Medico-Chirurgical Transactions, ii. 123; and in your Annals of Philosophy, i. 31.

P. S. I have often been applied to of late to know where the hydrometer for taking the specific gravity of urine may be purchased. It may be acceptable, therefore, to some of your readers, to know that a more easy method (and a preferable one, as it requires a much less quantity of urine, and no calculation) is to weigh the urine in a bottle which holds exactly 1000 grs. of distilled water at 60° Fahr. up to a mark on the neck. Bottles of this sort, with proper counterpoise, and decimal weights in a case, may be had in London of Mr. Knight, 41, Foster-lane, Cheapside; and, I dare say, of Mr. Accum, in Compton-street, and other makers of chemical apparatus.

VI. Atmospheric Phenomenon.

About a quarter before ten o'clock on Tuesday evening, Sept. 26, Fomalhaut being a little to the east of the meridian, the barometer being 29.62, and the thermometer 62°, a luminous band appeared near the western horizon, and extended itself gradually towards the east, until it occupied a line beginning at the sixth of the Eagle, passing through the Fox and Goose, between the fifth and sixth of the Swan, across Almaac, in Andromeda, and Medusa's Head and

terminating a little to the north of the Pleiades. It was very bright, and well defined near its western extremity; broader, fainter, and of shorter duration, towards the east. Its medium breadth was about five degrees, and it continued about 20 minutes.

The afternoon of Tuesday was very wet, with violent gusts of wind; for some time before this luminous appearance the sky was nearly covered with large dark Cumulous clouds, which passed away rapidly towards the N. E. and occasionally shot forth faint coruscations. The barometer and therinometer had been very variable for some days.

At eleven p. m. the sky was very bright near the northern horizon for about a quarter of an hour, but no Aurora Borealis appeared. No opportunity of observing the magnetic variation occurred at the time.

STR,

VII. Queries respecting Fluxions.

(To Dr. Thomson.).

As your correspondent Mr. Christison recommends the study of fluxions after the pupil has become acquainted with the second book of Euclid, he would render me an essential service if he would have the goodness to mention what work of this kind he thinks is best adapted to those who are already acquainted with the first six books of the Elements. Maclaurin's is the only one I have seen, but this appears too tedious and abstruse for a beginner, otherwise it appears to have great commendation, from the geometrical manner in which he introduces the subject. Should you, Sir, be so obliging as to notice this application, you will confer a favour on Your most obedient servant,

Sept. 21, 1815.

A SUBSCRIBER TO THE ANNALS.

VIII.

Connaissance des Temps, 1815.

SIR,

(To Dr. Thomson,)

I have felt some disappointment at finding that, in the last number of our Nautical Almanac, the phenomena and observations (occultations, &c.) have been almost entirely omitted. What is the cause of this serious omission? In the number for this year there are about 57 set down, in the column alluded to, for the twelve months; but in the Con. des Tems for this year, published in Nov. 1812, there are 218. Surely our ephemeris is not to become less valuable and interesting than that of the French in any respect. I have not great confidence in the accuracy of French printing, or I should prefer theirs. "Les occultations d'étoiles par la lune étant les phénomènes les plus utiles pour déterminer avec précision les longitudes géographiques, les voyagers ne doivent pas négliger de les observer; les conjonctions qu'on indique ici serviront à les guider pour prévoir les occultations qui pourront avoir lieu dans les