That Zimmermann was groping about blindly in search of the projectile Shrapnel found in 1784, is proved beyond a doubt by the question which the Feuerwerker puts to the Büchsenmeister: “Cannot a case shot be made which will leave the bore whole and burst at a few hundred paces’ distance?”[560] But Zimmermann failed in his search: what he sought did not lie on the road that he took. Like Fronsperger,[561] he placed his fuze next the charge, in consequence of which (as the old man frankly confesses) most of his cylinders burst in the bore: “Gemainlich im Stückh angegangen und zersprungen.” Boillot, a quarter of a century later, had a better knowledge of gunnery: “adviserez que le trou d’icelle (the fuze-hole) soit du costé de la bouche dudit mortier.”[562] Zimmermann filled the front half of his cylinder with bullets and the rear half with strong powder, obviously assuming the stability of the missile in its flight. Now Prof. Greenhill has given us a table showing the _minimum_ twist at the muzzle requisite to give stability of rotation to elongated projectiles. If a common shell’s length be 3 calibres, it requires a twist of 1 turn in 38.45 calibres; if its length be 4 calibres it requires a twist of 1 turn in 27.6 calibres; and so on.[563] How far, then, would Zimmermann’s ill-balanced, smooth-bore cylinder have travelled before it toppled over, with the certain result that, when it did, the large bursting charge would blow the bullets any way but the right way? Zimmermann’s projectile failed, and his sole merit consists in vaguely foreshadowing the Shrapnel, just as Roger Bacon dimly foresaw balloons and ships driven by machinery—“Marine engines can be constructed and worked by one man which will propel the largest vessels quicker than a ship’s crew of oarsmen.... Flying machines can also be made.”[564] His cylinder no more establishes Zimmermann’s claim to be the inventor, or even the suggester, of Shrapnel shell, than Bourne’s method of shooting “three times in a peece at one lading of her”[565] entitles him to be regarded as the inventor of quick-firing guns. We should have been spared much unprofitable controversy had foreign critics thought fit to make themselves acquainted with the nature and properties of Shrapnel’s Spherical Case before discussing its history. Its history is simple. It was made in England, the invention of an English Artillery officer who owed nothing to earlier gunners in Germany or anywhere else. CHAPTER XIV IGNEOUS PROJECTILES _Hot Shot._