322 



SCIENCE-GOSSIP. 



The third plate exposed for twenty seconds was 

 altogether the worst taken, from the failure of the 

 clockwork, yet it is most important from the 

 number of the prominences shown. The fourth, a 

 French plate, is interesting from its showing the 

 remarkable phenomenon known as Baily's beads. 

 M. Hansky's plate, No. i, taken with the camera, 

 had an exposure of " six seconds. The image of the 

 corona is intense and very well brought out. One 

 can follow the whole length of the ray from the 

 sun's limb for 70'. Of all the neighbouring stars, 

 Jupiter alone was obtained. There are no stars, 

 evidently because of the clouds which one can see 

 on the negative. The clearer prominences are also 

 shown." The plate is reproduced (fig. 3) as our 

 third illustration. 



The other plates were less interesting from the 

 slight displacement of the image and the clouds. 



Prince Galitzine was unfortunate with his first 

 two plates, which were from some specially pre- 

 pared for the eclipse, by Strezniewsky, and named 

 "Corona" plates, which, although they gave an 



image of the corona tolerably full of detail, and 

 intense, were yet fogged and spotted. His third 

 plate — a French one — proved more successful. But 

 the fourth, whilst very intense, suffered slightly 

 from fog as well as displacement. 



The work of the expedition being done, the exact 

 time determined, the instruments were dismounted. 

 The party afterwards joined Sir George Baden 

 Powell's, and, accepting his invitation, returned in 

 the Otaria, making a most pleasurable ending to the 

 expedition. The enjoyment was enhanced when at 

 Hammerfest they fell in with Nansen just returning 

 from his great polar expedition. 



Perhaps it should be added that the exact position 

 of the station, to the east of St. Nicolas Church, at 

 Malya Karmakouly, was E. longitude 3h. 30m. 

 50s., N. latitude 72° 22'-5. 



In closing, the writer has to express his acknow- 

 ledgment of assistance kindly rendered by Mr. 

 Harold S. Geikie in the important matter of 

 translation. 



60, Lenthall Road, Dalston, N.E. 



MANGANESE DEPOSITS IN GLACIAL DRIFT. 

 By T. E. Lones, M.A., LL.D. 



TN the gravel and sands which immediately 

 overlie the chalk in some parts of Hertfordshire 

 are black and reddish-black manganiferous beds 

 of an exceptional character. These beds, which 

 may be seen in some of the gravel-pits near 

 St. Albans, Aldenham and Watford, present a 

 marked contrast to, and may be easily dis- 

 tinguished from, the reddish-brown and yellow 

 beds amongst which they lie. As a rule the 

 manganiferous beds do not pass into but are 

 sharply separated from the underlying and over- 

 lying beds ; they are markedly lenticular, and 

 are rarely more than nine inches thick. The 

 manganese is present as black oxide in very fine 

 granules, forming a soot-like powder, part of 

 which encrusts the remaining constituents of the 

 manganiferous beds. These constituents comprise 

 angular and sub-angular flints, grains and pebbles 

 of flint, quartz, chalcedony and limonite. Some 

 of the limonite occurs as a pseudomorph after 

 flint, jasper and quartz. The proportions in 

 which the above-named constituents occur in the 

 manganiferous beds vary between wide limits, 

 whilst the proportion of oxide of manganese varies 

 from a small percentage up to about fifteen per 

 cent., by weight, in the richest samples taken from 

 the beds. By carefully washing a sample of the 

 deposits, the whole of the oxide of manganese, 

 mixed with flint, limonite, quartz, and other grains 

 of small size, can be separated from the rest 

 of the sample as a very fine, jet-black and plastic 



mass. A thoroughly dried sample of a rich mud 

 of this kind yielded, very nearly, on analysis : 

 Fe203, 1 7" I per cent. ; Mn02, 33"2 per cent. ; 

 silica as quartz, flint, etc., 5G'7 per cent. = ioo-o. 



In all the Hertfordshire gravel-pits, the richest 

 and most persistent deposits of oxide of manganese 

 occur in the lower parts of the gravel and sand. 

 In one of the pits near Watford an unusually thick 

 manganiferous bed occurs, but the percentage of 

 manganese is small. The beds are, in all cases, 

 horizontal or only slightly inclined. Collectively, 

 the beds appear to cover a large area ; the largest 

 bed at present exposed does not, however, appear 

 to extend over more than a few hundred square 

 yards. It is almost unnecessary to state, after the 

 above description, that the manganiferous beds are 

 too thin to allow of their being worked for the 

 oxide of manganese they contain. 



Judging from their general appearance and the 

 occurrence therein of numerous pebbles and 

 rounded quartz-grains, the manganiferous beds 

 would seem to have been deposited by the waters 

 of a river. All the pits in which the manganiferous 

 beds have been seen by me are not far from the 

 River Colne, and are within its valley. An 

 interesting question in connection with these 

 manganiferous beds is that relating to the determina- 

 tion of the origin of the oxide of manganese. It 

 is generally admitted that the pebbles of quartzite, 

 lydian-stone, and some other associated rocks found 

 in the drift, were transported by the action of ice 



