putrefied by the rain, and moisture of the dung in the bed, he found animalcula discoverable only by the third magnifier, floating in the liquor, squeezed out from it from which he thinks it evident, that the dangerous consequences which history has informed us to have attended the eating of mushrooms, have not arisen from any poisonous quality essential to them, but from the accidental ova or animalcula, which the richness of their nutriment has allured to them, and which their contiguity to the ground, and the places they are produced in, render

them obnoxious to.

It may not be amiss to subjoin a short account of the culture in the kitchengarden of a plant which contributes so much to the delicacy of polite tables, which may be depended on, from personal trial and success; as those few writers on the subject, not being acquainted with the true mushrooms, are not entirely to be depended on.

In the melonry, or place allotted in the garden for hot-beds, the mushrooms must be thus ordered: having marked out a portion of ground one yard and a half broad, and of any length, as the ground will permit; fasten two sticks at each end of the diametrical distance already marked out, which shall, by inclining to each other on the top, form an isosceles triangle. To the breadth and height of these sticks must the bed be made, of old, rich, dry dung, closely trodden together: neither new nor moist dung is proper; for the mushroom being naturally of a succulent and spongy contexture, too much heat, and too much moisture, must necessarily injure it. Having raised the bed to the height and breadth proposed, cover it with fine screened mould, to the thickness of 3 inches, into which, at proper distances, put either that white fibrous substance, which may be collected from the place where mushrooms have formerly grown; or else water it with water in which the chives and parings of mushrooms have been steeped ; or you may put in the chives in gross. If you take the first away, the mushroom is propagated by transplantation; that white fibrous substance, already mentioned, being no other than the stolones of old mushrooms, from which others are propagated, like potatoes: if you take the second, that is, by watering, the seeds lodged in the parings, being, by the water, separated from the siliquæ, and with it poured on the mould, are that which gives fertility to the beds thus managed. If you put the chives in gross into the mould, it is no more than sowing the seed in the pods, as in other plants it is sometimes necessary to do. Over the bed, thus prepared, must constantly be kept a covering of long new litter, to the thickness of one foot, to preserve the plant from the frost, the sun, and the wind. During the middle of summer, and the extremity of winter, it is best to make these beds under shelter; but at other times they are best exposed, the warm rains not a little contributing to their fertility; which, by the sloping fashion of the beds, are suffered to moisten them no more than necessary.

When speaking of the mushrooms, he means the fungus * porosus, crassus, magnus, called, by way of eminence, in England, the mushroom.

A Scheme of a Diary of the Weather; with Draughts and Descriptions of Machines subservient to it. By Roger Pickering, F. R. S, and V. D. M. N° 473, p.1. On a page of a folio paper book, opening broad-ways, are drawn, at proper distances, nine horizontal, and seven perpendicular lines; in the void square spaces of which the particulars of the diary are written down. The first of the horizontal lines is for the days of the month and week, on which the examination is made: the 2d for the hour of the day: the 3d for the weight of the air: the 4th for its heat the 5th for its moisture, or dryness: the 6th for the quarter of the wind: the seventh for its force: the 8th for the weather; as whether it be rainy or cloudy, or clear: the 9th for the quantity of rain; and the space between the last line and the end of the paper, for the bill of mortality.

The 7 perpendicular lines are for the 7 days of the week; which, in our diary begins with the first day, or Sunday. If you therefore carry your eye along the paper from left to right, you may at one view see the weight of the air, and the degrees of heat and moisture, &c. for the whole week. If you carry your eye from top to bottom down the column, for any one day, you see regularly the whole of the observations in one line for that day. Four pages, or weeks, we allow to each month, and then leave a void page for the observations made in that month; and the overplus calendary days are carried on to the page allotted for the next month; only taking care to describe in every such page, where the ending and beginning of two different months are to be found, the names of both the months, directly over their final and initial day. The abstract of the weekly bill of mortality is apparently a part of observation peculiar to this plan, under which article all acute cases, depending on the state of the air, are set down.

Of the machines necessary in making observations for a diary of the weather, are these five: 1. The Barometer.-Those with open cisterns are more sensible than the portable ones; and with a micrometer, that divides an inch into 400 parts, renders them capable of showing the most minute alteration of the gravity of the air. 2. The Thermometer.-One made by Fahrenheit's scale on one side, with its correspondence to the graduation of the alcohol thermometer on the other, is recommended.

All the machines, except the barometer, are exposed to the open air. The thermometer and hygrometer are placed in a little shed, made for their recep tion, against the study window, where the graduation could be seen through the

* Mr. Watson, a very skilful and ingenious botanist, remarked, that the mushroom here meant, is the Fungus campestris albus superné, inferné rubens. J. B. See Raii Synops. Stirp. Brit. Edit. secunda, p. 11.-Orig.

glass; and, by lifting up the sash, they can be taken in, as occasion requires.

Of the Hygrometer.-Mr. P. had, for some time, used Dr. Hooke's hygrometer, made of the beard of a wild oat, set in a small box, with a dial-plate and an index; but he soon found an inconvenience, without the remedying of which no dependence could be had on this machine; viz. its making more than one revolution in a night. He endeavoured to remedy this by the following method, described in fig. 17, pl. 1.

At the vertical point, from which moisture and dryness are graduated, a small circle is described; the lower arch of which should just intersect with that arch, round which the index of the oat described its circuit. In the centre of this small circle is placed a pin, easily turning in the central cavity, and furnished with a flat piece of thin ivory on its head. This piece of ivory, intersecting with the index of the oat, by it was turned either to the moist or dry side of its gra duation, as the index made a double revolution. Mr. P. flattered himself with success; but soon found, in the great fogs in the winter, that the wild oat is not a safe material to make an accurate hygrometer of. So he immediately turned his thoughts to some other for the diary, and reserved this for his study; where, or in any inclosed place, it does well enough, and may be very useful.

As a succedaneum to this, he thought on a statical one; it recurring to his mind, that the weight and moisture of the air being two properties of one and the same body, a statical hygrometer promised the best assistance towards a more complete knowledge of the barometer, which acts on statical principles; and that these two machines must have a reciprocal correspondence with each other. Remembering that Mr. Boyle had mentioned something of this nature; after consulting whom, he made the following machine, acting on his principles, but formed in a manner differing from his.

He procured a balance to turn with half a grain, the axis of the balance drawn out to the length of one inch, and its end furnished with a male screw, to which a light index with a female screw might be fixed. He had this balance fastened in a wainscot box, 12 inches in length, 9 in diameter, and 4 in depth at top, but gradually widening towards the bottom, with a back to slide up and down in a groove. The axis of an inch length, came through a hole in the front of the box, and then had the index fastened on, which described the segment of a circle on a brass plate, silvered and graduated into 180°, as if it had consisted of a perfect semicircle, or two quadrants.

The beam turning with half a grain; and every such turn, after repeated trials, moving the index somewhat more than one degree of the 180 described on the plate; he made a weight of 90 grains, which he fixed with a thread to one brachium of the balance, without any scale, the several threads or silk strings

of which, as they would imbibe more moisture, would make the machine less accurate; and the other brachium he charged with a sponge, suspended likewise by a thread, of such a weight, when reduced to absolute dryness, as made an equilibrium; and then screwing on the index to the first degree of the 180, and exposing the machine, thus ordered, to the open air, in one night's time the index had got to the 70th degree; which, as the sponge had been absolutely dry, must have been the true state of the air, as to moisture, at that time.

He found this machine extremely sensible and accurate; it would alter 10 degrces in a night, and as many in a day.

The near correspondence between the degrees on the graduated plate, and the weight of the moisture necessary to be imbibed or exhaled, to make either brachium of the balance preponderate every such degree, gives it the preference to any other. other. For a more perfect idea of this machine, see fig. 12, pl. 1, where it is viewed on the inside, the back being slid up. At fig. 13 is represented the plate with its graduations and index, as it should appear on the front of the case.

Of the Anemoscope, fig. 14, pl. 1. The Anemoscope is a machine 44 feet high, consisting of a broad and weighty pedestal, a pillar fastened into it, and an iron axis, of about half an inch diameter, fastened into the pillar. On this axis turns a wooden tube, at the top of which is placed a vane, of the same materials, 21 inches long, consisting of a quadrant, graduated and bound with an iron rim, notched to each degree; and a counterpoise of wood, on the other. Through the centre of the quadrant runs an iron pin, on which are fastened 2 small round pieces of wood, which serve as moveable radii to describe the degrees on the quadrant, and as handles to a velum or sail, whose plane is one foot square, made of canvas stretched on 4 battens, and painted. On the upper batten, next to the bound rim of the quadrant, is a small spring, which catches at every notch corresponding to each degree, as the wind shall, by pressing against the sail, raise it up; and prevents the falling back of the sail, on the lessening of the force of the wind. At the bottom of the wooden tube is an iron index, which moves round a circular piece of wood fastened to the top of the pillar on the pedestal, on which are described the 32 points of the compass. By which this instrument shows both the direction and strength of the wind.

The Ombrometer, or Rain-gauge, fig. 16.-This machine consists of a tin funnel, its surface an inch square, a flat board, and a glass tube let into the middle of it in a groove, and an index. His board was about 3 feet long, to answer the height of the rails that go round the top of his house, to one of which it is hung, clear of any obstacle to prevent the free fall of the rain, with 4 small staples that slide over as many tenter-hooks. The bore of the tube is about half an inch; which, at a medium, is the best size, a larger bore obliging you to make your graduation the more contracted, and consequently the less plain and accu

rate; and a less one not permitting you to return the water out of the tube when full, without the adhesion of a great deal to its sides; which, when you have placed the tube in its perpendicular situation, subsides, and sometimes fills up

of an inch; which, without care, must necessarily make great mistakes in the diary. The method of graduating the board is this:

He had a vessel of tin made, whose contents were exactly a cubic inch. With this vessel, filled with water exactly to its surface, he frequently gauged the tube, till, by repeated trials, he had found the height to which a cubic inch of water would rise in it. The space answering to this on the board he had graduated into 32 equal parts, and took the same method with the rest of the tube, till in the same manner he had graduated 4 such inches. Now the surface of the funnelbeing, as has been said, exactly a square inch, no rain can by it get into the tube, but such as falls within the square of one inch; which, as the shower is more or less, has its exact quantity shown on the board, on which a moveable. index is placed.

Of the Monthly Observations.-The vacant page at the end of every 4 weeks, reserved for observations occurring in the preceding month, and giving a summary account of the greatest difference of the weather in it, is a method peculiar to this diary; and one which will be allowed exceedingly pertinent and useful. The great end of this, and all diaries, is to furnish materials for a set of sound observations, on which to build a thorough knowledge of the atmosphere, and its effects on mankind: and it is easy to see what great advantage to this part of natural knowledge must arise from a variety of observations, made by different men of application and judgment, on one and the same subject. Besides, in this portion of our design may be included, what could not well without perplexity be thrown into the columns of the diary, all the meteorological appearances of the aurora borealis, lightning, thunder, &c. with abstracts of the most authentic accounts of such phenomena, as at any time in the preceding month have been seen in different parts of our own country, or abroad.

A description of the meteorological figures in pl. 1. In fig. 12, aaaa shows the hygrometer seen in the inside; bb the balance; c a small piece of wood, by which the balance is fastened to the box; d the sponge; e the weight; f, f, two little rings, by which the hygrometer is hung up.

Fig. 13, the graduated plate on the front of the machine; with its index and divisions.

Fig. 14, the anemoscope; a the pedestal; b the pillar, in which the iron axis. is fitted; c the circle of wood, on which are described the 32 points of the compass; d the index; e the wooden tube on its axis; f the velum; g the graduated quadrant; h the counterpoise of the vane.

Fig. 15, the velum taken off; a the plane of the velum; b the spring; cc the