In the middle of the eighteenth century Frederick the Great made considerable progress in Artillery organization, although the material was unchanged. He increased the number of guns till he had 5 or 6 to every 1,000 Infantry, which is to-day the proportion thought desirable. In 1759 he formed a light Battery with gunners mounted, so as to keep up with Cavalry. This Horse Artillery was eventually adopted by the Austrians in 1783, and by the French and British in the Revolutionary Wars. Frederick abolished Battalion Guns, and grouped them in permanent Batteries, the germ of modern _Field Batteries_, although drivers were not mounted, or made into soldiers, till near the end of the century. The heavier guns were still dragged by horses in single file, led by civilian drivers on foot, and were called “Guns of position.” They were generally formed in four masses--centre, wings, and reserve. After the Seven Years’ War these guns were everywhere formed into _Batteries_ of uniform calibre, which in France were called _Divisions_, and manned by one Company of the Artillery Regiment. The teams began to be harnessed in pairs, with the drivers mounted on the near horse. The modern battery system was thus introduced, and may be said to have been adopted in every army towards the end of the eighteenth century, when battalion guns were abolished. Batteries began to be brigaded by threes or fours during the early part of the nineteenth century. In England and France, about 1800, a corps of drivers for Artillery was formed, in which for the first time drivers had uniform and discipline; but these corps were abolished after 1820, and the drivers became an integral part of the Artillery. In Austria and Prussia, Batteries were allotted to _Infantry Brigades_, a system which was kept up in Prussia till after Waterloo, and in Austria till after the war of 1866. In France, during the Revolutionary Wars, the Batteries were allotted to _Divisions_, in the way which still holds. There was always, in addition, a mass of guns styled the _Reserve Artillery_, which we find during the Napoleonic Wars, and down to the campaign of 1870. By that time it had been converted in the Prussian Army into _Corps Artillery_, an arrangement which all other armies have since copied. About 1900, however, the Corps Artillery was abolished in Germany, and its batteries distributed to the Divisions. THE EVOLUTION OF THE ENGINEERS