Makcu 28, 1912] 
ctinium B was undoubtedly present. (New nomen- 
lature after Rutherford and Geiger, Phil. Mag., 
22, p. 621, is used throughout this communication.) 
Closer investigations of the conditions of this pheno- 
enon established the fact that this removal of the 
ctive products from the anode took place only in the 
ase when the activated plate serving as anode was 
sed during a preceding electrolysis of water as 
cathode, or, in other words, was previously electro- 
lytically saturated with hydrogen. This saturation of 
the plate with hydrogen was found as the necessary 
ondition for making possible the removal of the 
Tadio-active products from the anode. The atoms of 
he active deposit were driven under the action of the | 
mt 
erect applied electromotive force as ions into the pure 
water. If the plate had been previously sufficiently 
saturated with hydrogen, and used then as anode, it 
was possible by applying a great P.D. to drive from 
it into the water in a few seconds a great part, viz. 
‘up to two-thirds, of the active products deposited on 
it. On the other hand, it was not possible to deprive 
the plate of its total activity even by applying a P.D. 
_ of 840 volts, nor by electrolysis during half an hour. 
‘The more detailed results of these investigations will 
‘be given elsewhere. Tapeusz GODLEWSKI. 
Lemberg, Physical Laboratory of the Technical 
High School, March 18. 
} 
1 
Autophanous Eyes. 
i I HAvE been greatly interested by the correspondence 
ately appearing in Nature on the subject of eyes 
gleaming in the dark, and there are one or two 
oints about which I should much like to hear a little 
ore. 
| With regard to human eyes never glowing, I 
knew one case some years ago of a young Scotch 
girl whose eyes glowed with a distinct deep-red light. 
She was a fair-complexioned girl with auburn hair 
and the peculiar red-brown eyes which go with that 
colouring. 
_ On the subject of cats’ eyes, can anyone tell me 
“why the glow is invariably red in blue-eyed cats and 
'green with yellow or green eyes, as the glow is not 
| from the iris, but from the tapetum? I had a half- 
ersian cat for years with one blue and one yellow 
eye, and in the dark they were perfect little ‘‘ port” 
‘and “starboard” lights. The red glow of the blue- 
eyed cat, whether Persian or Siamese, is a deep ruby 
‘(not spinel like a mouse’s eyes), and is noticeable 
'even with tiny kittens before the colour of the iris 
is develoned at all. 
_ With Persian kittens it is possible to tell as soon 
as their eyes are open whether they will have blue or 
yellow eyes by placing them so that the glow can 
be seen, i.e. with a light in line with the observer’s 
own eyes, those which will later develop a blue iris 
showing like rubies, and the future yellow or green 
iris like emeralds. Having at present six Siamese 
Cats (fawn-coloured, with deep-blue eyes) and a 
Persian (black, with yellow eves), I have considerable 
| opportunities of observing them. 
CuartotTe I. WHEELER CUFFE. 
Brachead, Kokine, Rangoon, March 1. 
” 
Tue phenomenon of *‘ glowing ’’ eyes (autophanous 
r not) is certainly observed in man. Without taking 
uch interest in the matter, I have noticed three 
ases, one abroad and years ago, and the other two 
uite recently in London. In Room to of the L.C.C. 
echnical Institute, Dalston Lane, N.E., with all 
lights switched on, I observed the phenomenon over 
‘and over again by standing between the lecturer’s 
table and the front bench and looking down at the 
Student sitting in the middle (who should be looking 
up at you). I should add that I assumed the matter 
NO. 2213, VOL. 89] 
NATURE 
| arity of the one student. 
87 
to be a function of the position after I had seen it in 
two students; before then I thought it was a peculi- 
H. ve S.-P. 
Sibpur College, Calcutta, March 7. 
RAND GEOLOGY.! 
| Fs no other part of the world is the work cf 
the geologist linked up with such varied in- 
terests as in the little strip—some fifty miles long 
— of high tableland in the Transvaal known as the 
Witwatersrand, on which are situated some sixty 
producing gold-mines with an annual output of 
350 tons of fine gold, worth 35,000,000l.; and, 
indeed, in no other district has the geologist such 
Opportunities for prosecuting his researches as 
are afforded by the innumerable prospecting 
trenches, shafts, and deep borings that have been 
put down on the Rand in the search of extensions, 
along the strike and on the dip, of the auriferous 
conglomerates. Hundreds of thousands of pounds 
have been spent on prospecting work of this 
nature. In one area alone near the Springs, in 
| the East Rand, the writer of this review had the 
| technical supervision of a series of deep borings, 
costing above 30,o001., and successfully located 
the eastern end of the Witwatersrand syncline, 
with its valuable gold-bearing seam there con- 
cealed beneath a thousand-foot cover of the later 
unconformable Dolomite formation. 
The Transvaal Geological Survey, which, since 
its reconstruction after the war, has been working 
mainly in the northern part of the Transvaal, has 
at last broken ground on the Witwatersrand, and 
the report for r9ro0 contains an important instal- 
ment of this work, in which Dr. Mellor? sum- 
marises the results of his mapping of the lower 
Witwatersrand beds between Maraisburg and 
Rietfontein, an area including the municipality of 
Johannesburg and the Bezuidenhout valley, the 
geological structure of which presents so many 
points of interest. The main features of this area 
have long been known : they were sketched broadly 
by Walcot Gibson in a paper read before the 
Geological Society in 1892; and the boundary lines 
of the various subdivisions of the Witwatersrand 
beds were mapped by Messrs. Hatch and Cor- 
storphine, and published in the Transactions of 
the Geological Society for South Africa for 1g04. 
Dr. Mellor’s mapping of these subdivisions 
agrees in the main with that of his predecessors ; 
but he explains the duplication of the lower Wit- 
watersrand beds by a new reading of the faulting, 
which on his view took place subsequently to the 
extrusion of the Klipriversburg amygdaloid. His 
map also records a hitherto unnoticed strip of 
sheared granite on the farm Rietfontein No. 145, 
that throws fresh light on the age of the move- 
ments responsible for the dislocations. The pub- 
lication of the further work of the Survey on the 
Rand, especially at its extreme eastern and 
western ends, will be awaited with interest. 
1gto, Union of South Africa 
1 Report of the Geological Survey for 
i 113, with g plates and 5 maps 
Mines Department, Pretoria, rg1t. Pp. 
Price 7s. 6d. : ¥. 
2 “The Geology of a Portion of the Central Witwatersrand.” By E. T. 
Mellor. Pp. 22-38 of the Report. 
