1. In the Mathematician for March, 1849, Dr. Rutherford inserts his "New and Simple Process for determining all the three roots of a Cubic Equation;" this paper is dated "February 2nd, 1849," and contains a reference to the tract on equations "recently published."

2. In the Phil. Mag. for "March, 1849," Professor Young refers to Dr. Rutherford's tract; and as this paper is dated "Belfast, Feb. 15th, 1849," the Professor must have been in possession of a copy previously to this date.

3. From a private note to me dated "Feb. 24th, 1849," it appears that Professor Davies had then read the pamphlet. I ordered the work for myself, through Longman's, on "January 23rd, 1849;" the answer returned was "not out," nor did I succeed in obtaining a copy until "March 9th, 1849," as appears from a reference to my bookseller's day-book for that period.

4. Professor Young claims for Mr. Davies the "essential principle" of Dr. Rutherford's method in the Phil. Mag. for April, 1849, p. 282; and Mr. Davies himself maintains his priority in the suggestion of the principle in a Note on Numerical Transformation," inserted in the Phil. Mag. for May, 1849. The former communication bears date "Belfast, March 8th, 1849," and the latter, "Royal Military Academy, Woolwich, April 6th, 1849."

It hence appears that copies of Dr. Rutherford's tract were in the hands of mathematicians early in February, 1849, and that the publication, most probably, took place in "January, 1849," as the preface intimates. My copy contains several press errors apparently corrected by the author himself, and hence we may reasonably account for the difficulty of procuring early copies.

I am, Sir, yours, &c.,

THOS. T. WILKINSON.

Burnley, Lancashire, July 9th, 1851.

THE PENDULUM EXPERIMENT.

Sir,-As the pendulum experiment has created considerable interest, and as many, like your correspondent Mr. Rozzell, can fully understand how the plane of vibration apparently rotates 15o per hour at the pole and remains stationary at the equator, but cannot comprehend why it should vary in intermediate lati

tudes, I send you the following experiment, by which I think they will be able to practically demonstrate the fact:

Construct a parallel ruler of two pieces of fine steel wire, four or five inches long, and capable of opening out to two or three inches wide. Fix on a globe, at any latitude (say 30°) a circular piece of paper representing the table and rule, a line across the centre to represent the plane of vibration, say from north to south. Place one arm of the parallel ruler directly over and in a line with the pencil-mark, hold it firmly, and turn the globe through 15°; bring the other arm over the centre of the table, and rule a line. Now remove the ruler, and placing it over the last mark, turn the globe 15° more, and draw another line. Repeat this operation every 15° until the globe has revolved 90°, and you will have a paper with seven lines on it thus:

Now repeat this process with the table affixed to another latitude (say 700) and you will have a paper with the seven lines thus':

Try it in several latitudes, and it will be found that, whereas at the pole the lines marked on the table will correspond with the number of degrees through which the globe has been turned, so they will gradually describe a less and less angle as you approach the equator, where there will be no deviation what

• ever.

It is not necessary, though perhaps more convenient, to commence with the plane of vibration in a line with the meridian; and the process, if wished, may be continued during an entire revolution of the globe.

WILLIAM ROBINSON, of Holsham, York, machinist and agricultural implement maker. For improved machinery for separating corn from straw. Patent dated January 11, 1851.

This machine, which is intended to be used in conjunction with an ordinary thrashing machine, consists of a rectangular framework, across which extend a series of axes parallel to each other, some having two and others three radial flaps (thin strips or leaves of wood or other material), projecting 'rom them, and of equal length with the axes. The axes, which are placed at such distance apart as to allow room for them to revolve without bringing the flaps in contact, have mounted on them pinions gearing into each other, and are caused to revolve at a rapid rate, and with the same linear velocity. By the shaking action thus produced the corn is effectually separated from the straw, and falls through the spaces between the axes, whilst at the same time the straw is gradually carried forward and delivered from the machine.

Claim. A series of flaps or flies in a frame, arranged to receive the straw from the thrashing machine, and separate the corn therefrom whilst the straw is carried forward.

JOHN CORRY, of Belfast, damask manufacturer. For improvements in machinery or apparatus for weaving figured fabrics; which machinery or apparatus is also applicable to other purposes for which Jacquard apparatus is or may be employed. Patent dated January 2, 1851.

The improvements here claimed have relation to Jacquard apparatus, and comprehend:

1. The application as a substitute for the cards ordinarily employed in such machines, of a perforated metallic sheet, covered with

paper, parchment, or other similar material, on which is painted, drawn, or traced, the pattern or design intended to be produced on the figured fabric, which pattern or design so painted, drawn, or traced, is afterwards punched out by means of suitable punches, and thereby holes or perforations produced which answer the same purpose as the holes punched in the ordinary cards.

2. A peculiar arrangement of Jacquard apparatus, in which the bent wires to which the harness is attached are arranged in one, or not more than two rows, instead of being in several rows, as at present; in which also the needles are combined with the bent wires in such a way as to act thereon by means of their heads or ends, and being kept in contact by the bent ends of the wires, which act as springs.

3. The exclusive use of needles which act on the bent wires by means of their heads or ends striking against them, the heads or ends being enlarged for the purpose, instead of being provided with an eye or loop through which to pass the needle, as in the present arrangement.

JOSHUA HORTON, of Etna Works, Smethwick, steam-engine boiler and gas-holder manufacturer. For improvements in the construction of gas-holders. Patent dated January 2, 1851.

The main object of the present improvements is to dispense with guide standards of the usual great height, and to employ instead standards of about half the height of the holder when afloat. The claims are

1. The use of vertical travelling guide standards fixed to the lower or outer gasholder, to which standards friction rollers, wheels, or pulleys are attached, which work against guide-plates or bars, for the purpose of keeping the holder in a steady and upright position during its rising and falling, caused by the increase or diminution of the quantity of gas contained therein.

2. The application of guide-bars or plates fixed to and forming part of the sides of the gas-holder, instead of being loosely attached thereto, as in the ordinary construction of gas-holder.

3. A peculiar method of forming the hydraulic cups for the water joints of the different parts of the holder, by bending the metal of which the top and bottom are composed into a cup shape, so that the joint may be made complete, and attached to the sides of the holder without the necessity of employing angle iron and double sets of rivets for the purpose.

JOHN TATHAM and DAVID CHEETHAM, of Rochdale, machine-makers. For certain improvements in steam engines, in apparatus for generating and indicating the pres

sure of steam, and for filtering water to be applied to boilers: also improvements applicable to steam vessels or ships. Patent dated January 2, 1851.

The improvements here claimed are

1. The application to locomotive engines of an additional cylinder or cylinders, in which the steam exerts its expansive force after having actuated the piston in the first cylinder. [In the arrangements described, the additional cylinder is placed either at the end of the first, and has its piston attached on the same rod as the main cylinder, or it is placed above it, and the two pistons are connected by a crosshead, so as in both cases to work simultaneously in the same direction.] Also, a method of transferring the point of attachment of the crank connecting rods with the driving cylinder to a point behind the end of the cylinder from which the piston rod or rods issue. [In this arrangement the patentees employ an annular cylinder, with a piston of corresponding shape. The piston is connected by two piston rods to a crosshead, at the centre of which is another rod, which slides in guides in the circular space at the centre of the cylinder. The connecting rod of the crank driving shaft is attached to the end of the crosshead rod which works in the guides, and by these means the object above mentioned is attained, and the driving power may be brought within a very short distance of the crank shaft.]

2. The application to steam boilers of transverse tubes to connect the flues, when such flues are constructed in the direction of the length of the boiler.

3. The application to steam boilers of a chamber beneath, and extending about half the length, for the purpose of receiving sedimentary impurities. [The chamber is provided with a cock for drawing off the sediment at required intervals.]

4. The employment of a fan for causing the products of combustion, after passing through the boiler flue, to be drawn through a series of tubes, and facilitate the generation of steam by heating the feed-water for the boiler.

5. The placing of the fire-bars of furnaces in a direction transversal to the fire-door. [According to this arrangement, a part of the bars may be replaced when worn by exposure to the fire, which cannot be done to advantage when the bars are placed in the opposite direction.]

6. The employment in apparatus for measuring and indicating the pressure of steam of a column of mercury, which is caused to overflow by an undue pressure of steam, and by its gravity opens the safety-valve.

is

7. The application of a filter for purifying the water employed for injection into the condenser. [The patentees describe two arrangements of filter adapted for this purpose. The first of these consists of a casing, within which is a double cylinder of perforated zinc or metal mounted in horizontal bearings, and capable of revolving. The space ace between the perf perforated cylinders filled with wool or fibrous materials, through which the water passes, and after being thus purified, it is drawn off by a pump and injected into the condenser. An air pipe is provided leading to the interior of the cylinder, in order that in certain cases the pressure of the atmosphere may be allowed to be exerted on the water contained therein, and thus the action of the exhausting pump be facilitated. According to the second arrangement, the cylindrical filter occupies a vertical position, and is made stationary instead of being moveable]

8. The employment of steam, conducted through suitable pipes, for extinguishing fire on board ships. (The arrangement of the pipes, which should in all cases be provided with suitable cocks, must be varied with circumstances, such as the build of the vessel and the situation in which they are required to be placed.]

THOMAS LAWES, of the City-road. For improvements in generating and applying steam for certain purposes. Patent dated July 4, 1851.

The improvements sought to be secured under this patent comprehend

1. A peculiar construction of tubular boiler, in which the tubes are arranged in alternate horizontal and vertical lines, and provided with plugs to admit of their being cleared out when necessary.

2. An apparatus for drying feathers, hair, wool, &c., by the aid of steam pipes enclosed within a cylinder, to which a rotary motion is communicated when the materials have been placed therein.

3. The application to locomotive engines of an intermediate toothed driving wheel gearing into a rack or toothed rail placed between the ordinary rails, and provided with suitable means for lifting it out of gear.

Specifications Due, but not Enrolled. BENJAMIN COOK, of Birmingham, manufacturer. For a certain improvement or certain improvements in the manufacture of metallic tubes. Patent dated January 3, 1851.

JOHN PERCY, of Birmingham, doctor of medicine, and HENRY WIGGIN, of the same place, manufacturer. For a new metallic