1851 Great Exhibition: Official Catalogue: Class X.: Hayward Brothers
298. HAYWARD BROTHERS, 196 Blackfriars Road - Inventors and Proprietors.
Gauge for measuring the thickness of metal and other plates, rods, or bars:—The principle of this gauge is the progressive movement of an accurately cut screw, to which is affixed a dial or circular index, which may be divided so that each space shall indicate that the screw has advanced the 1000th part of an inch, or otherwise marked as may be required, such as to show the aliquot parts of an inch, the weights per foot super., etc., of any particular metals, alloys, or other material, whose specific gravity is known, or with any arbitrary line of numbers, such as the ordinary wire gauge.
The gauge which is exhibited has the outer circle set out, so that each minor division is equal to 1 oz. per foot super. of sheet-iron sp. gr. 7.68, the quarters and lbs. being shown up to 20 lbs. to the foot. The relative weights per foot super. of any other metals, etc., may be found from the sliding or circular scale of equivalents which accompanies the gauge. The next circle has a line of numbers, which are suggested by the inventor of the gauge, as an improved scale for universal adoption; the advantages being that each whole number will tell its own particular value in 100ths of an inch, with fractions added, expressing 1000ths; and if written thus, "12, 14, etc., could not be mistaken for the whole numbers, 12,
14, etc., as might be the case in ordinary commercial transactions. If placed with the decimal point only, for substances less than 100ths of an inch, the numbers might be written 01, 02 to 09, each representing 1, 2 to 9 thousandths of an inch respectively. The inner circle gives the numbers of the present Birmingham wire gauge, or (as commonly known) "the wire gauge," by which are measured iron, brass, and black steel-wires, iron and steel-sheets, and many other articles.
If the weight per foot superficial of sheet-iron be required, the screw is turned to the left until there is more than sufficient room to admit the plate to be measured; then the instrument being supported with the fingers of the left hand in such a manner as to press the three points against the under side of the plate, and the thumb being placed on the plate to hold the gauge firmly, leaving the screw perfectly free, from the relative position which this bears to the three points, it will rise and descend at right angles with the face of the plate. Now the screw being turned slowly to the right, until its further progress is obstructed, in the outer circle on the dial, against the perpendicular line inside the case, will be shown the weight of the plate in ounces and lbs. to the foot superficial of sheet-iron, sp. gr. 7.68.
For measuring wire, the screw should be turned to the right, until the wire cannot pass between it and the point immediately under it; then the wire being gently pressed between the two, and the screw turned slowly to the left until the wire passes, the number of the wire will be found in the inner circles on the dial.
Sliding and circular scales of equivalents for weights:— If the weight per foot superficial of any other material than iron be required, it is placed in the gauge, and then on the outer circle is found the weight which it would be if sheet-iron; this weight being found on the slide, and placed against the "iron-sheet," opposite to the name of the material on the fixed part of the rule, on the slide, will be shown the weight per foot superficial of that which is under examination; and against all the rest, their respective equivalents. The scale is also applicable to all other calculations of relative weights: thus, the weight of a casting in iron is found from the weight of the model, by finding its weight on the slider and placing it opposite to the article of which it is made; then on the slider opposite to cast-iron, will be found its weight in this material, the customary allowance beimg made for the shifting of the model, and the contraction of the iron as it cools. If the whole numbers, instead of being called lbs., are taken as cwts., then the ounces will each represent 7 lbs. If the lbs. are called ounces, then the ounces will represent drachms.
Circular scale:— In this scale the same results are obtained by moving the various articles which are set off on the centre, opposite to the weights on the stationary margin.
Sheringham's registered ventilator.