Page:Proceedings of the Royal Society of London Vol 60.djvu/432

400 Very strong band from 5598 to 5485. Band of continuous rays with other bands discernible in it. Less refrangible edge of band 5445. Band in the same at 5422, 5390, 5359, 5341, 5322. The more refrangible edge of band 5304. Very narrow band in the blue, more like a very strong broad line from 4222 to 4215.

The magnesium oxide was identified by three bands, more or less connected by diffused rays.

1st. From 3929 to 3856 2nd. „ 3834 „ 3805 3rd. „ 3805 „ 3682

On these bands were seen ten iron lines, six in the first principal group and four in the second, all very faint, but with apparently the following wave-lengths, which correspond with the lines seen in oxyhydrogen flame spectrum of ferric oxide. They are also closely in approximation to, and probably identical with, the following arc lines, measured by Kayser and Bunge in iron.

3860*03 3856*49 3826*04 3824*58 3758*36 3748*39 3745*67 3737*27 . 3735*0 3722*69 3720*07

Roasted Cleveland Iron Ore. Process for the Extraction of Gallium.

This ore is a complex substance, and contains elements which render the complete extraction of the gallium very difficult. It is in great part soluble in strong hydrochloric acid, but the iron goes into solutions as a ferric salt, and difficulties arise in attempting to reduce it. to the ferrous state. Zinc and iron are both liable to contain gallium, and, without a very careful examination of a quantity of the metal, it would be wrong to use them as reducing agents, seeing that the quantity of metal required in the process is large in comparison with the sample treated. Sulphurous acid and kindred substances yield sulphates which cause a quantity of the alkaline earths to separate as sulphates, and, as these precipitate in faintly acid solutions, there is a risk of basic gallium sulphate being carried down with them. # <.

Dilute hydrochloric acid yields a solution poor in iron, but the dissolved matter is richer in gallium than the original ore. A large proportion of silicic acid is, however, contained in the solution.

Experiments were made on quantities of 50 grams of the ore, and the spectra from the sesquioxide metals were carefully compared with the spectra from the similar products from the metal, and we find that, as in the comparison of the original samples of ore and