Deutoxide of Lead 104 Protosulphurets of Lead and Silver 104 Nitrate of Barytes 113 Protoxide of Mercury 174? Deutoxide of Mercury 181? Protosulphuret of Mercury 181 Alum 277 ADDENDA. STEEL.--Since writing the article at page 214, I have had an opportunity of analysing the crystalline steel, formed by Mr. Macintosh’s process of cementation by means of coal gas. I dissolved 21 grains of this steel in sulphuric acid, with only a very slight excess of acid. The whole was dissolved except about ⅒ of a grain of silvery-like particles. The gas obtained amounted to 29.6 cubic inches. It yielded no trace of carbonic acid. When fired with oxygen it yielded 3 per cent. upon the volume of hydrogen of carbonic acid; and this arose, as I ascertained, from the hydrogen containing 3 per cent of carburetted hydrogen gas: it contained no carbonic oxide. Supposing the carbone to have been combined with the iron, it would amount only to about ⅝ of a grain, to 100 grains of iron. Whether such a quantity can be deemed an essential or an accidental ingredient of steel, may be a subject of consideration. _By a mistake of the Printer, the following paragraphs were omitted after page 308._ EXAMPLE. According to the following values of the different specific gravities, (of the accuracy of some of which there may be doubts) and referring to my essay on oil gas (Manchester Memoirs, Vol. 4, new series, page 79,) we may take the oil gas, which, when the incombustible portion was abstracted would be nearly .812 sp. gravity, and 100 pure gas give 152 carb. acid and take 248 oxygen; Here _w_ = 100, _a_ = 152, _g_ = 248, _S_ = 1.458, ∫ = .555, _c_ = .972 _s_ = .0694 and _C_ = .812. The value of _u_ reduces to the following form; _u_ = 4.7916_a_ - 1⅔_g_ + 1.875_w_ - 6_C__w_ -------------------------------------------- = 24.5 .625 hydrogen per cent. of pure combustible gas. Hence we have 75.5 volumes left for the 3 other ingredients = _w_ of the formula; and abstracting 12 + from the oxygen on account of the hydrogen, _g_ = 236, and _a_ = 152 as above. Whence _x_ = Superolefiant = 38¼ _y_ = Carb. hydrg. = 30.2 and _z_ = Carb. oxide = 7+ ----- 75.5 These results differ considerably from those deduced in the above essay; probably in part from errors in the above estimates of the specific gravities of one or more of the gases. EXPANSION OF LIQUIDS BY HEAT. I am not aware of any particular labour that has recently been given to the enquiry how far pure liquids accord with each other in the law which I announced as derived from the experiments on water and mercury, and corroborated by those upon several other liquids. See Vol. 1, Table of temperature, page 14; also page 36, and following.