1874.] Notices of Books. 255 
evident that the reader is under the guidance of one who is 
familiar with the results of shore and dredge collecting, and long 
and patient aquarium observations. 
A considerable space is devoted to the structure of insects. In 
remarking on their eyes and ears, the author writes: ‘It is not 
impossible, judging from the great diversity which we find in the 
form and structure of these and similar organs in this immense 
class of beings, compared with the uniformity that prevails in the 
organs of sense bestowed in ourselves and other vertebrate 
animals, that a far wider sphere of perception is open to them 
than to us. Perhaps conditions that are perceptible to us only 
by the aid of the most delicate instruments of modern science 
may be perceptible to their acute faculties, and may govern their 
instinéts and actions. Among such we may mention, con- 
jecturally, the comparative moisture or dryness of the atmosphere, 
delicate changes in its temperature, in its density, the presence 
of gaseous exhalations, the proximity of solid bodies indicated 
by subtle vibrations of the air, the height above the earth at 
which flight is performed, measured barometrically, the various 
electrical conditions of the atmosphere ; and perhaps many other 
physical qualities which cannot be classed under sight, smell, 
taste, or touch, and which may be altogether imperceptible, and 
therefore altogether inconceivable by us.”’ 
It is to be regretted that the author should have contented 
himself with borrowing a cut on page 151, representing the 
proboscis of the blow-fly, instead of supplying a figure more in 
accordance with recent observations drawn by himself. 
The work can be safely recommended as a guide to those 
really in earnest as to their microscopical studies, and will prove 
an admirable companion to those who take their microscopes to 
the sea-side during the approaching summer holidays. 
A Handbook of Practical Telegraphy. By R.S. CuLttey, Member 
Inst. C.E., Engineer-in-Chief of Telegraphs to the Post- 
Office. Adopted by the Post-Office and by the Department 
of Telegraphs for India. Sixth edition, revised and enlarged. 
London: Longmans, Green, Reader, and Dyer. 1874. 8vo., 
PP- 443- 
It is a sure sign of the high estimation in which Mr. Culley’s 
work is held, and of the soundness of his electrical knowledge, 
when we find that his volume has already reached its sixth 
edition. Holding a foremost position in his profession, and sur- 
rounded by the whole telegraphic network of the British Isles, 
he necessarily constitutes the centre towards which a vast mass 
of electrical and telegraphic information naturally concentrates ; 
and, as a consequence, his writings may be considered the digest 
of these experiences. 
