328. 5. Sandarac, Seed-Lac, and Shell-Lac, must be finely pounded and sifted, before they are used.
329. The Author having examined different Kinds of varnished Silks, in different Places, does, from their Excellence, recommend those made by Fawkner, Umbrella-Maker, Alport-Street, Manchester; a Person wholly unknown to him, but from the Merit of the Work: which consists not only in the Varnish itself; but in the peculiar Method of applying it, which the Author is not at Liberty to make public.
Fawkner can warrant his Silk Air-tight; soft and unadhesive; durable, and unalterable by that Excess of Heat and Cold, to which the Balloon is, at the same Time, subject; viz. internally, to the hot depredating and caustic Fumes, rising with the Gass: and externally, to the Sun, Wet, Frost, and Drought.
CHAPTER LXIV.
HINTS ON IMPROVEMENT OF THE MACHINERY.
Section 330. IN order to make Improvements of the Balloon still more rapid and general; the Society for the Encouragement of Arts, who have given no particular Encouragement, in Imitation of that at Lyons, to the much-wished-for Art of directing the Balloon;—might offer a Premium for different Inventions of a propulsive Machinery, the Models of which are to be made at the Expence of the Society, within a certain limited Sum: and, without condemning what cannot be known unless by repeated Trials,—give Encouragement for such Trials: the Models to remain with the Society for public Exhibition.
331. Also, Figures and Explanations of such Machinery as have been tried, viz. the Fly or Moulinet of Blanchard; and of those which have not succeeded for Want of Trial; might be sent by the Inventors, in order to perpetuate the Invention, either to the Society of Arts; or to the Editors of creditable Magazines, who woud be glad of such ingenious Acquisitions, as it woud be a Means of procuring Purchasers, and circulate the Knowledge of this gigantic Infant Science.
Improvement woud then go on apace, and in a Chain: each Labourer forging and finishing his respective Link.
Whereas at present every one is obliged to find his own Materials, sink the Foundation, raise and finish the Building. And hence so little Work is done, worthy the Inspection of a skilful Architect.