[Illustration: FIRE-EXTINGUISHING APPLIANCES, SQUIRTS, BUCKETS, ETC., A.D. 1667.] Judging from some Instructions of the Corporation after the fire, hand-squirts and ladders and buckets were still chiefly relied upon in 1668. The Instructions are, moreover, interesting, as showing what action the Corporation took after the Great Fire. The city was divided into four districts, each of which was to be furnished with eight hundred leathern buckets, fifty ladders varying in sizes from 16 to 42 feet long, also "so many hand-squirts of brass as will furnish two for every parish, four-and-twenty pickaxe-sledges, and forty shod shovels." Further, each of the twelve companies was to provide thirty buckets, one engine, six pickaxe-sledges, three ladders, and two hand-squirts of brass. Again, "all the other inferior companies" were to provide similar appliances; and aldermen were likewise to provide buckets and hand-squirts of brass. The pickaxes and shovels were for use in demolishing houses and walls if necessary, or dealing with ruins; and though some kind of engine is mentioned, we know not whether it was a hand-squirt mounted in a cistern, or some sort of portable pump. We may regard these regulations, however, as fixing for us the hand-squirt and the bucket as the principal means of fire extinguishment in Britain up to that date. But now a great development was at hand, and a new chapter was to commence in the story. CHAPTER IV. THE PEARL-BUTTON MAKER'S CONTRIVANCE. THE MODERN FIRE-ENGINE. How to force a continuous stream of water on the fire! That was the problem which puzzled an unknown inventor about the year 1675. He probably saw that hitherto the appliances for extinguishing conflagrations failed at this point, and we may suppose that he cudgelled his brains to hit upon the right remedy. Then one day, no one seems to know when, he thought of inventing, or adapting, the compressed air-chamber to a sort of portable pump, and, behold!-- The Modern Fire-Engine was born! The invention was introduced, probably, after the Great Fire, because authorities describe it as first mentioned in the French _Journal des Savans_ in 1675, and Perrault states that an engine with an air-chamber was kept at Paris for the protection of the Royal Library in 1684. If, therefore, Hero knew of the air-chamber, as some assert, it does not appear to have been much used. But probably the great disaster in London stirred invention, and the addition of the air-chamber was the result. It may not, however, have been a distinct invention, for an air-chamber had been found of great value in various hydraulic machines. What, then, is this invention, and what is its great value to a fire-engine?