Remarks on the foregoing Tables.
REMARKS ON THE FOREGOING TABLES.
Table I gives the dimensions of Rocket moulds when the Rockets are rammed solid; it was calculated, as its Author informs us, from repeated experiments; we insert it for the information of our readers, but we would advise none to practise the method of solid ramming.
Table II.—This table may be perfectly understood by the explanation given of its use, and from considering that a lead bullet of a pound weight, is just 19½ lines in diameter, as may be proved by experiment; the inferior numbers are likewise the diameters of the inferior weight.
Table III.—This table is only an extension of the latter, although its arrangement is somewhat different; for if 19½, the diameter of a ball weighing one pound, be assumed as unity with any number of cyphers, answering to the number of parts which the same diameter is divided into, (which may be done by means of the diagonal scale,) let this number be 100, which answers to one in the column of pounds:—that is to say, if you assume 100 for the first number, and it be rose to the third power,[11] your first cube will be 1,000,000, the cube root of which (being 100) must be placed in your table as the first root, and answering to unity in the column of pounds: then for the second number, which is two pounds, we must extract the cube root of double that number, viz. 2,000,000, which will be 126 nearly, (or continued to more places 1,259,921) and this will be the second number in your Table; and in the same manner will the third number be found, that is, by trebling the first cube and extracting the root as before, which will be 144, and so of the fifth, sixth, &c. to the end of the table. These tables are indispensable in the making of Rockets, in order to preserve an uniformity in Rockets of the same kind, and to render more certain their effects, as has been corroborated by repeated experiments.