212 
POPULAR SCIENCE REVIEW. 
that artists are found to have been taking liberties with nature. The 
declivities in the mountains of Samuel Bough’s Loch Lomond,” a picture 
that has been engraved and published during the past year by the Associa- 
tion for the Promotion of the Fine Arts in Scotland, are shown by Mr. Bow’s 
scientilic test to be exaggerated to the extent of fifty per cent. Similarly, 
comparing the famous pictiu’e by Mr. Waller Paton, Edinburgh from the 
Echoing Rocks,” with a photograph taken from the same spot and verified 
by the theodolite, he finds that the true slope of the notable debris of Salis- 
bury Crags forms an angle of thirty- eight and a-half degrees with the 
horizon, while the artist (one of the highest standing), has made it to be 
not less than fifty degrees. In like manner science makes the moon to 
subtend a certain angle ; artistic licence makes it to be seven and a-half 
times larger than it really is. Apropos of this, in a recent political parody 
of ‘‘ The Fighting Temeraire,” in which both sun and moon are visible, the 
artist had apparently considered scientific accuracy so little a matter of 
moment that he had actually turned the crescented moon, in its relation to 
the sun, back side foremost. 
Photographs of Authors. — A bookseller in Paris has just started a novel 
idea, that of placing a photograph of the author on every book which he 
places in his window. He has evidently studied human nature to some 
purpose. 
PHYSICS. 
Cohesion-figures. — In a recent communication on these extremely inter- 
esting physical phenomena, Mr. Charles Tomlinson gives an account of the 
substances which may be employed to exhibit cohesion-figures. Solid 
carbolic acid, in small fragments, rotates on the water surface with immense 
velocity, after the manner of camphor. (Camphor also may be tried, but 
the fragments should be scraped from a freshly-cut surface with the point of 
a pen-knife.) If a needle of the commercial acid be placed on the water, it 
darts about suddenly, liquefies, forms into a disc, from which angry-looking 
waving forked tongues proceed, and so it wastes away. If the liquid acid be 
used, care must be taken to deliver it gently to the surface, or it will slip 
through and form an inert globule at the bottom of the water. Carbolic acid, 
or a mixture of this and cresylic acid, forms an active vigorous figure, and if a 
drop be placed on the same surface with what is left of the lavender figure, 
the mutual attractions and repulsions form a surprising sight. Cresylic acid 
leaves delicate silvery flakes on the surface of the water, and in this way 
the presence of a few drops per cent, of this acid in carbolic acid can be 
detected. — Vide Chemical Neivs, No. 447. 
Telescopic Photography. — The Photographic News states that M. Schroder, 
of Hamburg, is at present occupied in constructing a telescope to be fitted 
with clock-work, for photographing the heavenly bodies. The instrument 
is so arranged that the object to be reproduced will be considerably enlarged 
before it is thrown upon the sensitised plate. 
A Method of Mewing the S’olar Prominences . — At a meeting of the Royal 
Society, in February, Mr. W. Huggins stated that, on the 13th of that 
