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~Filtration.~--Solutions are best filtered hot whenever the assay allows of this being so done. The precipitate should be allowed to settle, and the clear liquid decanted on the filter with the aid of a glass rod if necessary. The filter-paper must not be too large, but at the same time it must not be overloaded with the precipitate. There should be ample room for washing. For general use three sizes of filter-paper are sufficient. Common quick filtering-paper (English) is best for most work in assaying. The specially prepared paper (Swedish or Rhenish) is used for collecting those precipitates which have to be weighed. The papers are folded as shown in fig. 16, and should not project above the funnel. The filter-paper works better if damped with hot water. In special cases filtering is hastened by means of an air-pump. The apparatus used consists of a water-jet (fig. 17), which is connected with the tap, as also with a bottle fitted as shown in fig. 18. The pump draws the air out from the bottle, and atmospheric pressure forces the liquid through the filter-paper. The bottom of the funnel is provided with a platinum cone, which supports the filter-paper, and prevents its breaking. The pump is only used in exceptional cases; nearly all the filtrations required by the assayer can be made without it. The usual methods of supporting the funnel during filtration are shown in fig. 19. Where the filtrate is not wanted, pickle bottles make convenient supports. After the precipitate has been thrown on the filter, it is washed. In washing, several washings with a small quantity of water are more effective than a few with a larger quantity of that fluid. The upper edge of the filter-paper is specially liable to escape complete washing. Excessive washing must be avoided; the point at which the washing is complete is found by collecting a little of the filtrate and testing it. The precipitate is removed from the filter-paper for further treatment by opening out the paper and by washing the precipitate with a jet of water from a wash-bottle into a beaker, or back through the funnel into the flask. In some cases, when the precipitate has to be dissolved in anything in which it is readily soluble, solution is effected in the filter itself allowing the liquid to run through as it is formed.

The foreign dominions of Rome now comprised the ten following provinces, to which is added the date of the formation of each: 1. Sicily, B.C. 241. 2. Sardinia and Corsica, B.C. 238. 3, 4. The two Spains, Citerior and Ulterior, B.C. 205. 5. Gallia Cisalpina, B.C. 191. 6. Macedonia, B.C. 146. 7. Illyricum, probably formed at the same time as Macedonia. 8. Achaia, that is, Southern Greece, virtually a province after the capture of Corinth, B.C. 146, though the exact date of its formation is unknown. 9. Africa, consisting of the dominions of Carthage, B.C. 146. 10. Asia, including the kingdom of Pergamus, B.C. 129. To these an eleventh was added in B.C. 118 by the conquest of the southern portion of Transalpine Gaul between the Alps and the Pyrenees. In contrast with the other portions of Gaul, it was frequently called simply the "Provincia," a name which has been retained in the modern Provence.

This boat was 72 feet in length, and her greatest height was 12 feet, while the greatest breadth was 8 feet, tapering off to points at the end. Capt. Murray Sueter in his book on submarines gives these and other particulars of the vessel. At either end the boat had a cabin, the air in which remained good for about three hours, and in the middle of the boat was a large paddlewheel rotated by clockwork mechanism, which, it was claimed, would run for eight hours when once wound up. The iron tips at the ends of the vessel were intended for ramming, and the inventor was confident he could sink the biggest English ship afloat by crushing in her hull under water. The boat was duly launched, but on trial of the machinery being made the paddlewheel, though it revolved in air, would not move in the water, the machinery being not powerful enough. This, says Capt. Sueter, was apparently the only reason for de Son's failure, for his principles were distinctly sound, and he was certainly the first inventor of the mechanically propelled semi-submarine boat. After her failure de Son exhibited her for a trifle to any casual passer-by.

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