ART. XVII. Miscellaneous Intelligence.

I. MECHANICAL SCIENCE.

§ 1. ASTRONOMY, AGRICULTURE, THE ARTS, &c. 1. Prize Question for 1820.-The Royal Academy of Sciences of Naples proposes the following subject to be rewarded with a prize, in the year 1820.

The description of an instrument is required, 1. which shall unite in itself the properties of the largest and most perfect meridian circles and meridian telescopes that have yet been made; 2. the verification of which shall not depend on any spirit level; 3. which can traverse and turn with facility, so as to allow of observation in two contrary positions; 4. and which can be made by any good workman possessed of the means offered by the actual state of the arts.

The memoir, to be accompanied by designs of the instrument, may be written either in Latin or Italian.

The prize to be awarded for the successful execution of the above conditions, will be a gold medal of the value of six hundred ducats. The memoirs, without the name of the author, but distinguished by a motto, are to be sent before the termination of February, 1820, to Il Cav Teodoro Monticelli, Secretary to the Royal Academy, and enclosed to the Secretary of State for external Affairs. The prize will be awarded on June 30, 1820, and the Memoirs not approved of returned, on demand, to the authors.

2. Rate of Increase in the Vegetation of Wheat.-The following experiment was made in Sussex. In October, 1818, twelve. grains of wheat were planted at six inches' distance from each other. They all vegetated, but one third was afterwards destroyed by the worms. The remaining crop having flourished, was reaped in the beginning of August, the eight grains producing 213 fine ears, or nearly 27 ears, of 39 grains each, from each seed sown. The crop being threshed and cleaned amounted to 124 ounces of corn. From this result, expanded by calculation over an acre of ground, are drawn arguments for

the more accurate culture of grain than is generally adopted in this country.

3. New Stop-Cock for Pneumatic Apparatus.-In consequence of the frequent imperfection of the common stop-cock for the retention of condensed atmosphere, Sig. Crivelli, Professor of Natural Philosophy at Milan, has invented another, which is supposed to be free from the objections that may be made to the first. The annexed diagram will explain its construction,

b

a

000 d

It consists of a box a, and plug b, both of the usual form; also a conical valve c, and a spring tube d. The aperture in the end of the stop-cock, from e to ƒ is conical, and carefully ground. The other part inwards is cylindrical; the valve is a metal rod extending from c to g, and made conical in the part corresponding to the aperture just now described, so as to fit it with great accuracy. This valve is retained in its place in a shut position by a small spiral spring in the tube d, which tube screws on to the worm e. The side of the box corresponding to the other aperture h, has no appendage, but is finished by having a groove cut in its inside, nearly half way round i, and level with the valve and the aperture. The plug of the cock is not bored, but has a groove cut in it, k, deepest in the middle

of its length, and passing off gradually into the general surface of the plug, so as to form a kind of inclined plane on it. This groove extends half way round, and is so arranged that when the plug is put into its place, it shall receive the end of the valve c, the length of the valve, and the depth of the groove being such that the former may perfectly enter into and close the conical aperture e, when its extremity c is in the middle of the groove. Now, it is evident, that whilst the cock remains in this state, it is shut against the passage of any gas through it, not only by the conical valve, but also by the disunion of the two grooves; when, however, the plug is turned, the plane, which the groove in it forms, presses on the end of the valve, and opens it either more or less, according as it is more or less turned round, and, at the same time, the end of the plug groove passing over the end of that in the box, opens a channel, by which the gas passes off, which has already made its way by the valve. The emission of the gas may, in this way, be regulated with great nicety, and its retention, if 'required, secured in a very perfect manner. The plug is retained in its place by the screw l, or, as in the usual manner; and, it is evident, that the end e of the stop-cock is that which is to be inserted into the vessel intended to contain the gas. Sig. Crivelli has particularly applied these stop-cocks to the condensed air blow-pipe.-Giornale di Fisica. T. 2., p. 92.

4. Substitute for a Copying Machine.-Write with common writing ink, in which lump sugar has been dissolved, in the proportion of four scruples or a drachm and a half of sugar to an ounce of ink.

Moisten copying paper, (a paper which is sold at the stationers at 1s. 10d. a quire for the Copying Machines,) by passing a wet soft brush over it; then press it gently between soft cap paper, so as to smoothen it and absorb the superabundant moisture.

Put the paper so moistened upon the writing, and both between cap or other smooth soft paper, placing the whole on the carpet or hearth-rug, one end of which is to be folded over it.

By standing and treading upon this, an impression will be taken equal, if not superior, to what would have been taken by a Copying Machine.

5. Dry-Rot prevented.-The following method of preventing dry-rot is recommended. This destructive visitant in dwellinghouses generally grows and originates in the cellar. If persons white-washing cellars will mix as much copperas with the wash as will give it a clear yellow hue, and repeat this every year, they may prevent the dry-rot, or stop its progress, if it has already appeared.

6. Ancient Seeds.-In the highest point of a field on the farm of Craignarthro', a mile south from Forfar, in Scotland, there was a druid's place of worship, consisting of a circle of large stones, with one, the largest, in the middle. The field was fallowed last year, and this temple trenched, from which a very great quantity of stones were turned up. Nothing particular, however, appeared, except a few bones that went to dust. The field, this year, was sown with barley, and this trenched part with the rest; now, so far as this space extended, there are considerable quantities of oats of various kinds, sprung up among the barley, the seeds of which, must have remained there more than 1,000 years. Without the trenched ground, there is not a head of oats to be seen. Orders have been given to preserve these oat-plants.-New Monthly Magazine.

7. Smut in Wheat prevented. The following process is recommended in the Bibliothèque Physico-Economique, as the only one which experience has proved effectual against the smut in wheat. To destroy the germ of the blight in 4 bushels, or 256 pounds of corn, about six or seven gallons of water must be used, according as the grain is more or less dry, and from 35 to 48 ounces avoirdupois of quick-lime, in proportion as it is more or less caustic, and according to the extent of the blight. Slack the lime in a portion of the water heated, and then add the rest. The heat of the whole quantity of

the water should be just bearable by the hand. It is then to be poured upon the corn, placed in a tub, stirring it continually, at first with a stick, and then with a shovel. The fluid should, at first, cover the wheat three or four fingers' breadth, but it will soon be absorbed by the grain. It should remain in this state twenty-four hours, being turned over five or six times in the interval. Whatever fluid will drain off is then to be separated, and the seed, after standing a few hours, so that it may run freely out of the hand, may be sown. If not to be used immediately, it should be put in a heap, and moved once or twice a day till dry.

This grain germinates sooner than unlimed grain. It germinates with more certainty, and insects will not attack it.

II. NATURAL HISTORY.

§1. MINERALOGY, GEOLOGY, &c.

1. Mineralogical Notices, &c.

MR. EDITOR,-Sir,

During my late tour into Derbyshire, I was pleased at meeting with compact fluor, which has not before been noticed, to my knowledge, in that county; it occurs sometimes covered with beautiful cubic crystals of opalescent yellow fluor. Another variety has frequently been called kevel.

In a level driving from Castleton-town, in a west direction, to the Odin mine, and, in the stratum called shale, several small calcareous veins were cut; from one of them some fine crystallizations were obtained of the primitive rhomb, and from another, rushed a current of air of small magnitude, which inflamed when a lighted candle was applied to it. In one instance it burnt all night, but it was exhausted in a few days. Some years ago, perhaps thirty, I have heard of the miners selling sp. cimens of green selenite; they occurred in the Odin mine: latterly, some very fine phosphates of iron have been met with in that neighbourhood: it is doubtful if what were called green selenite were not phosphates of iron. In the shale, this substance is common, appearing as a blue powder, but it is VOL. VIII. 2 A