a 
OcToBER 2, 1913] 
the principles of scientific illumination in their rela- 
tion to the use of gas for lighting. . 
‘Many ways have already been suggested and 
demonstrated for causing each eye to see its appro- 
priate picture of a stereoscopic pair, but we learn 
from The Times of September 26 that Messrs. Fried- 
mann and Reiffenstein are showing yet another at 
the Austro-German Medical Congress now being held 
in Vienna. The new method depends upon the fact 
that a white image is invisible on a white back- 
ground, and a black image is invisible on a black 
background, while both are visible if the backgrounds 
are reversed. The authors therefore bleach the nega- 
tive of one of the pair, make an ordinary trans- 
parency from the other, and superpose the two plates. 
This compound plate will show either the one or the 
other picture according as the background put behind 
it is light or dark, and if the background is arranged 
so that it appears light to one eye and dark to the 
other—that is, light or dark according to the side 
that it is viewed from—then each eye will see its own 
picture without any instrumental means. A_back- 
ground that serves this purpose is a sheet of glass 
that is ‘‘ribbed convexly,” while its back surface is 
“prepared in a special manner’’ that is not described. 
The great advantage of such stereoscopic pictures is 
that they only need looking at as if they were single 
pictures to show the full stereoscopic effect. It is 
stated that the few specimens shown are very satis- 
factory. 
Tue provisional programme of the Royal Geo- 
graphical Society for the coming session has just been 
issued. We learn from it that the following papers 
have been arranged :—‘‘ The Work and Adventures of 
the Northern Party of Capt. Scott’s Antarctic Expedi- 
tion,” R. E. Priestley (November 10); ‘‘ Explorations 
in the Eastern Karakoram,’’ Mrs. Bullock Workman 
and Dr. Hunter Workman (November 24); ‘Is the 
Earth Drying up?’ Prof. J. W. Gregory, F.R.S. 
(December 8); ‘An Expedition to Dutch New 
Guinea,’ A. F. R. Wollaston (December 16). In 
addition to the foregoing, the following papers may 
be expected:—‘‘Famous Maps in the British 
Museum,”’ J. A. J. de Villiers; “Journey through 
Arabia,” Capt. G. E. Leachman; ‘‘ Geographical 
Aspects of Two Sub-Expeditions in the Antarctic,” 
Griffith Taylor; ‘The Federal District and Capital, 
Camberra, of the Commonwealth of Australia,” 
Griffith Taylor; ‘‘Journeys in the Upper Amazon 
Basin,” Dr. Hamilton Rice; ‘‘The Gulf Stream,” 
Commander Campbell Hepworth, C.B.; ‘‘The Red 
Sea and the Jordan,” Sir William Willcocks, 
K.C.M.G.; ‘‘Fresh Discoveries in the Eket District, 
Southern Nigeria,” P. A. Talbot; ‘“'The Panama 
Canal,”’ Dr. Vaughan Cornish; ‘t The Atlantic Ocean,” 
Prof. E. Hull, F.R.S.; ‘‘The Anglo-German Boun- 
dary Survey in West Africa,” Capt. W. V. Nugent. 
In L’Anthropologie, vol. xxiv., Nos. 2 and 3, Pro. | 
G. H. Luquet proposes an explanation of the rock | 
markings at Gavr’inis. Comparing the figures with 
those on the megalithic monuments in Brittany and 
Ireland, he suggests that they are ultimately based on 
NO. 2292, VOL. 92] 
NATURE 
I4I 
an anthropomorphic attempt to represent the human 
figure, particularly of the eyes and eyebrows. This 
contribution is lavishly illustrated by woodcuts, and 
the explanation now offered well deserves respectful 
study by archzologists in this country. 
Mr. ANANDA Coomaraswamy’s useful periodical, 
Visvakarma, devoted to the reproduction of examples 
of Indian architecture, sculpture, painting, and handi- 
crafts, has reached its fifth number. We have a fine 
series of photographs, among which the most notice- 
able are the splendid lion column from Sarnath, the 
Trimurti or sacred triad from the Caves of Elephanta, 
and interesting figures of deer, monkeys, a cat and 
mice from Mamallapuram. The Asokan statue from 
Besnagar is one of the most remarkable sculptural 
remains of the period. 
Tue National Geographic Magazine for September 
is devoted to Egypt, and contains a large collection of 
beautiful photographs. Perhaps the most interesting 
contribution is the account by Mr. C. M. Cobern of 
the sacred ibis cemetery and jackal catacombs at 
Abydos. The ibises are as carefully mummified as 
the royal personages at Deir-el-Bahari, and were it 
not for the ravages by white ants, hundreds of these 
sacred birds could now be examined in as perfect a 
state as when they were buried. The jackals were 
preserved because they were sacred to Anubis, the 
friend of the righteous dead, who guided the soul 
across the trackless desert to the fields of Aalu, the 
land of the dead. 
THE excavation of the Roman city of Corstopitum, 
the modern Corbridge, begun by the Northumberland 
County History Committee and the Corbridge Excava- 
tion Committee in 1906, was actively prosecuted 
during the past season. Among the objects unearthed 
were forty-eight gold coins and a gold ring, probably 
deposited about a.p. 385, several altars, a vast quantity 
of pottery, a bronze pig containing 160 gold coins 
ranging from Nero to Marcus Aurelius, the well- 
known Corbridge lion, a smithy with arrow-heads and 
other articles of iron. Thus a vast amount of 
material for the ‘study of Roman pottery has been 
found, and the buildings include some of the most 
imposing relics in Roman Britain, as well as some of 
the worst walls ever erected by human hands. The 
animal remains are of high scientific value, and some 
addition has been made to our knowledge of Roman 
metallurgy. The museum has been rearranged, and 
now contains a collection of Roman remains un- 
equalled in the north of England, except, perhaps, at 
York. 
WE have to acknowledge the receipt from Messrs. 
Dulau and Co., Ltd., of a copy of a catalogue of 
works and papers on various groups of the lower 
invertebrates. 
In the report of the museums of the Brooklyn 
Institute for 31912, reference is made to the large 
increase in the zoological collections, and the mounting 
of a group of marsh-hawks for the series illustrating 
the fauna of Long Island. Of the fauna and flora of 
: that island a popular account is in course of publica- 
