482 Royal Institution. 



Composition of the residue insoluble in hj' drochloric acid : — 

 Silica, soluble in dilute caustic potash. . . . 0"98 

 Silica, insoluble in dilute caustic potash. . 0'52 

 Alumina with a trace of peroxide of iron. . O'lO 



lltanic acid, about 003 



Lime trace 



1-63 



The ore contains no metal precipitable by sulphuretted hydrogen 

 from the hydrochloric acid solution. 



In the residue insoluble in hydrochloric acid, minute, bright, black 

 crystals were detected, which were proved to contain titanium, and 

 were supposed to be anatase. Prof. Miller of Cambridge has been 

 able to measure certain of the angles, and found them to be 

 identical with similar angles of anatase. I'he discovery of this 

 mineral in the Cleveland ore is at least a point of considerable mine- 

 ralogical interest, and may possibly furnish some additional indica- 

 tion of the nature of the rock from which it was derived. 



The silica in the insoluble residue exists, it will have been ob- 

 served, in two states, about two-thirds being soluble in dilute caustic 

 potash, and one -third insoluble in that solvent. The rounded white 

 particles, which, according to Bowerbank, have a truly oolitic or con- 

 centric concretionary structure, are entirely formed of the soluble silica. 



The silica which existed in the hydrochloric acid solution was that 

 which was present in a state of combination in the ore, probably 

 with both protoxide and peroxide of iron ; and the peculiar greenish- 

 grey colour of the ore was doubtless due to the presence of this sili- 

 cate of the mixed oxides of iron, just as the colour of the green par- 

 ticles in the so-called greensand is believed to be due to the like cause. 



The proportion of phosphoric acid in the ore is comparatively 

 large, and may be easily accounted for by the fossiliferous character 

 of the ore. The quahty of the iron smelted from this ore would cer- 

 tainly be very sensibly affected by the proportion of phosphorus, and 

 probably also by the silica existing in a state of combination. 



5. " On the occurrence of Coal near the City of E-u in China." 

 By the Rev. U. H. Cobbold. Forwarded from the Foreign Office. 



The coal is worked by shafts and galleries in the hills near E-u, a 

 third-class city, in the prefecture of King-hua, from which it is 

 distant forty English miles by water. The pits are from 300 to 500 

 feet deep. The coal is bright, and not bituminous. 



KOYAL INSTITUTION OF GREAT BRITAIN. 



April 4, 1856. — " On the Measurement of the Chemical Action 

 of Light." By Henry E. Roscoe, Esq., B.A., Ph.D. 



No attempt has been made, up to the present time, accurately to 

 measure the changes brought about in chemical substances by the 

 action of the solar rays. 



The peculiar action of light on chemical bodies was first ob- 

 served by Scheele on chloride of silver. Since that time the 

 subject of the chemical action of light has attracted a large amount 

 of attention, as the present perfection of the arts of the daguerreo- 

 typist and photographer fully testify. Although we possess so 



