cinth or garnet, melts readily into a slag, in a common furnace, a sufficient distinction between them. Where found.

They are found in Arabia, Calicut, and Cambaya. The occidental in Poland, Bohemia, and Saxony. The hyacinth garnet, in Spain and Groenland. Rufsia produces also this gem in the mountain Adanfhollo in Dauria, so fertile in precious stones. Born has just given us a new species of cruciform white hyacinth, found in Saxony. The chrysoletre is a variety of the hyacinth, (some say a spurious one,) so called from its resemblance to amber.

How valued.

Wallerius values the oriental hyacinth at from twenty to fifty dollars per carat, according to lustre, colour,

c

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1

SIR,

HINTS ON MACHINERY.

To the Editor of the Bee.

was much pleased with your ingenious explication of the chain with buckets*, to the purpose of creating circular motion, where there is an high fall of a small rill of water. I was only astonished (as we always are upon the discovery of things that on explication appear obvious) how so simple a contrivance fhould so long have escaped observation; and this I conceive to be the highest commendation that can be bestowed on any new invention.

Your paper suggested several thoughts to me which I have thrown together;-if you reckon them worth insertion, you are welcome to them. I am *Bee, vol. xi, p. 150.

but a novice in mechanics, and I could not on my own judgement say whether they are so or not.

From what you have observed, I am convinced that the impetus of water is a moving power of little importance in proportion to its weight and of the water wheels now in use I therefore conclude, that the bucket wheel gives more force from equal quantities of water pafsing in equal times. Of the bucket wheels, too, I would prefer those which are so constructed as to admit the water immediately into the bucket which is in the direction of the horizontal diameter of the wheel, where its weight must have most energy, in virtue of the longest lever. I think, however, I have remarked, in some overfhot bucket wheels, that the water is immediately admitted into that bucket which has just passed the perpendicular of the wheel. Perhaps an idea is entertained of thereby accumulating more water upon the descending side of the wheel; though this conception must certainly be erroneous, as will evidently appear from this simple consideration, that, of necefsity, every perpendicular, revolving in a circle, must become an horizontal in turning round one quarter of the periphery of the circle. Supposing, then, the buckets to stand perpendicular when they are filled, they must gradually slant towards an horizontal direction, and consequently gradually empty themselves as they turn round, so as to become horizontal, and consequently empty, by the time they have traversed the quadrant of the circle. It therefore appears to me impofsible, by any contrivance, to load with water more than one quarter of the cisVOL. Xiii.

R

Jan. 23, cumference of the wheel at one time. This being admitted, it must certainly be the best mode to have the filled buckets always at the horizontal diameter, where their weight has most force, and where they will continue most full, in proportion as their position is most favourable for energy; rather than to have them filled where their weight has least force, with their weight gradually diminishing, in proportion as they come into succefsive positions where their weight would have been of more avail.

In every mode of construction of wheels with buckets, it is, however, evident, that there must be a considerable waste of the power of the water pafsing in a given time. 1st, In the lofs of the water, from the buckets emptying themselves, in proportion as they recede from their perpendicular to their horizontal direction. 2d, In the diminished action of the water which remains in the buckets, in proportion as they are nearer to the perpendicular than to the horizontal diameter of the wheel. These two circumstances of inaptitude to the production of the full effect of the given water, are common to every used species of the bucket wheel; and where the water is conducted upon the wheel by a trough, there is a third lofs of such water as pafses through the interstice, which must necefsarily be left, to allow of the motion betwixt the trough and the wheel.

In your most ingenious contrivance of the chain with buckets, none of these lofses are sustained. The whole water that pafses is brought to act upon the chain; except the inconsiderable spurt by the water dashing upon the thin edge of the bucket

which comes in to be filled; and this action is uniformly directed to the place where its energy is greatest. The only lofs of power is that which arises from the friction of the chain upon the wheels, at the top and bottom of the fall of water *; and this I am convinced would be trifling in comparison of the gain in every other respect. I doubt not but that by interposing your chain betwixt the water and the wheel, more force might be obtained than by even the bucket wheels in use, in any given situation where such wheels are used. As to the situation of small rills and high falls, andoubtedly a very great moving power may be commanded by your contrivance, where none could be obtained by the methods which have hitherto been devised.

I waited with impatience for the farther suggestions you promised upon the mode of applying the power of water where there is a current merely, but no fall, and, mean while, was forming my own conjectures upon the subject. Your proposal did not occur to me, though I am convinced it would answer in the case of rivers, in flat countries, as you suggest, and streams from lochs, which are not subject to sudden rises; and I doubt not but the immense force procured as an operating power, might compensate the expence of such extensive machine

* The ingenious writer, by looking back to the plate, vol.xi.p.250. wi!l observe that there can be no friction of the kind he here mentions, owing to the joints of the chain being of the same length with the distance between the bars of the wheels; so that the chain never slips upon it. The small friction that will arise from the bending of these joints, deserves, in practice, to be considered as nothing.

Edit.

ry. What occurred to me was but a very humble proposal in comparison. It was, merely to apply to the water wheel the principle commonly adopted by those who have attempted the perpetuum mobile*, which I fhall endeavour to explain.

Let the water, then, be conducted to the wheel by a conduit, provided with a sluice, that you may always have it in a regulated quantity. Let your wheel be made of a smaller diameter; but let the awes, as they are vulgarly named, or float boards, be fixed upon arms that are fixed into the wheel, of two, three, or four feet in length.

Let these arms be provided, each with two or three joints †, which might open towards the water

The only principle upon which I have had occasion to see the perpe tuum mobile attempted, is the recurring overbalance of the descending side of the vertical wheels; and this endeavoured to be effected by hollow tubes in the wheel, extending as radii from the center to the circumference, in which are inserted cylinders of wood, which project outwards, or retire in the descent and ascent of the wheel; or else moveable balls, or quicksilver, are inclosed in the tubes for a similar purpose.

An intelligent farmer of my acquaintance tried the experiment of flying, by means of canvas wings stretched upon wooden ribs, provided with joints of this kind, which could fhut close and open to the straight, like a man's hand. In raising the wings, they faut close, so as to meet with no resistance from the air. In giving the stroke, they expanded to a large surface. He succeeded so far as to raise himself off from the ground by a stroke of the wings, but he came down always before he could fetch a second. Oars might be constructed to advantage in this way. They would operate like the webbed feet of water fowls, without the necessity of raising them from the denser medium to the more rare, to diminish the resistance in fetching the stroke. A boat might be constructed in which a man might stand upright, the boat entirely under water, and the man sunk breast deep. He might work it in any direction with oars which would emit no sound, nor be visible to the eye; a narrow wooden trough might be fastened to his breast, to push before him, where he might deposit his