The construction of nails or tacks above described, may be varied when the top end or knob of the shank or stem, can be conveniently spread out as large as the head of the nail or tack, for in that case the dish or part c, at the back or under part of the head may be despensed with, by bending in or turning under the edge of the face or top piece b, as above described, and causing it to embrace the enlarged knob or head of the shank.

The Patentee in conclusion observes, that the separate parts, which when confined in the manner above described, constitute his improvements in manufacturing nails or tacks for ornamenting boxes and articles of furniture, may be made of various sizes, according to the intended size of the nail or tack, and they may be prepared by any of the known ordinary means at present in use for cutting and pressing metal, none of which form any part of his invention; but he claims as his invention, the combination of parts in the manner described to constitute a nail or tack for ornamenting boxes and articles of furniture, and which he believes to be entirely new and never before to have been practised by any other person whomsoever.—[Inrolled in the Roll's Chapel Office, September, 1831.] Specification drawn by Mr. Newton.

TO BENJAMIN GOULSON, of Pendleton, near Manchester in the county of Lancaster, surgeon, for his having invented or found out certain improvements in the manufacturing of farina and sugar, from vegetable productions.-[Sealed 14th December, 1829.]

THE Patentee proposes to prepare from carrots, turnips, beetroot, mangelwurzle, or potatoes, or any other roots of that kind which may be conveniently obtained, a fine white and nutritious farinaceous substance, capable of

being converted to the best white bread, and to all the purposes of fine wheaten flour; and also into sugar.

The roots are to be washed perfectly clean, or deprived of their skins, and are to be cut into thin slices. and then submitted to the action of a solution of acid in water; sulphuric acid is to be preferred, but any of the other acids will answer the purpose. The quantity of acid to be employed will depend upon the roots to be acted upon: from two to ten pounds of acid will be required for every hundred weight of roots; carrots will require the smallest quantity of acid, potatoes the greatest.

This steeping of the roots in the solution of acid, will perfectly change their characters and taste, and when they have been sufficiently acted upon, the acid and other matters held in solution, are to be removed from the slices of the roots, by washing them repeatedly with pure water. They may be afterwards dried by exposure to the air and sun, or by a kiln at a low temperature; and when the mixture has been evaporated, and the slices of the roots brought to perfect dryness, they may be submitted to the operation of a mill, and ground into farina or white flour in the ordinary way.

The slices of roots thus prepared will retain their nutritious properties unimpared for any length of time, and in any climate, if not exposed to damp; and the flour obtained from grinding them will have exactly the same properties, appearance, and flavour, as wheaten flour.

In preparing sugar from the said roots, they are to be washed and sliced, and submitted to the action of the acid in the way above described, and then reduced into farina, as a first part of the process. The farina is then to be boiled with a solution of acid, in the proportion of about two pounds of the acid to one hundred weight of the farina. A saccharine matter is produced by this

1

operation, which my be crystallized or granulated into sugar, by the ordinary mode of evaporating cane juice, or other vegetable extracts from which sugar is commonly made.

Instead of reducing the roots to a farinaceous powder, as last described, for the production of sugar, they may be steeped in their raw state in a solution of acid, in the proportion of ten pounds of acid to every hundred weight of roots; and after having been acted upon by the acid for about three days, the saccharine matter will be produced, which may be treated as before described, and sugar obtained therefrom.—[Inrolled in the Inrolment Office, June, 1831.]

To the Editor of the London Journal of Arts and Sciences. SIR,-I have latterly been engaged in putting up some wheel geering that required great accuracy, so as to enable them to run as smooth as possible; and I consider that I have succeeded in so doing; the plan adopted, I believe possesses some originality, and I therefore send it to you for publication, if worth your notice. This ground is so well treated by various authorities I have read, that little is to be expected of novelty. I have tried various curves for the teeth of wheels, but find none answer so well as the epicycloid. The Technical Reposi'tory, published 1822, (Vol. I.) contains some very valuable information on this subject.

VOL. VIII.-SECOND SERIES.

F

to

In the wheels made for me on a late occasion, there was no allowance for clearance. The cogs and spaces being equal, except at the tops and bottoms of the teeth, and only so much that light was barely visible; in a very few revolutions the wheels run as smooth almost as belt or band.

To obtain truth, and with but little trouble of calculating for odd members required, I availed myself of the following geometrical construction, for finding the circumference of a circle from its diameter, and which will be found to contain no error beyond 00000,1, of the latter to the former, and that I consider never could be discovered in workmanship of the most exquisite fiinish.

Take the diameter of any wheel or circle with compasses and step it from A, to B, and to D, (see the diagram in Plate III, at figure 17), on a horizontal or base line, upon which raise a perpendicular, and again step upon it the same distance from A, to M, N, K; again scribe, and intersect the arcs made from B, D, meeting in E; from E, and D, do the same, with the same distance, meeting in cross arcs at F; upon D, raise a line parallel to A, K, intersecting the line B, F, in c, and upon this describe the circle G, H, O, P,—c, K, will be the circumference of a circle, of which G, c, is the diameter: the error being something less than one hundred-thousandth part of the distance G, c. It follows therefore, that if c, be the centre or joint of a sector, a proportional compass or callipers, the opening of either will express or point out the circumference and diameter of whatever circle or wheel may be required at one and the same time.

If it be required to have an odd number of teeth in a wheel, say 67, one inch pitch, for tooth and space, lay off a straight line equal to 67X2=134 divisions, stretch the sector to this line K, L, and it will be the diameter-o, P,

of the proportional compasses or callipers, will be the same of course.

If it be required to cut a wheel from a solid blank circle of metal, to have, say 43 teeth of inch pitch, and that the proportion of teeth be also given as to the thickness and height, each shall have, viz. 4-5ths or 3-4ths of its height to be the thickness, reduce either proportions to a decimal, and divide this decimal into 3,1416,-the quotient resulting therefrom will be the number of spaces to be added to the line K, L, for the tops of teeth, or deducted therefrom for the circle that bounds the bottoms of the teeth; polygons of prime numbers may readily be found out by this means.

You will observe the compass to be used with this geometrical problem is never to be altered from first to last in forming its construction.

I think if this subject had the attention of some of the mathematical instrument makers directed to it, something practically useful to wheel makers might result.

I remain, yours very truly,

Bank of Ireland, Dublin.

JOHN OLDHAM.

P. S.-I know not whether you may consider there is any material novelty in the construction of the castor described here by sketch. I had several sizes made for myself and others, for sofas, beds, and tables, which have performed much better than any I have yet seen. The spindle A, is a fixture in the boot socket c, and rests upon its point in spindle socket B. The friction by this arrangement is considerably reduced.