68 SOME NEW BOOKS [suLY 
A HISTORY OF EXPERIMENTAL PHYSICS. 
Geschichte der physikalische Experimentier-Kunst. By Drs. GERLAND 
and F. TRAUMULLER. 8vo, pp. xvi.+442, with 425 illustrations. 
Leipzig: Engelmann, 1899. 
To trace from their hazy beginnings the gradual and laborious development 
of what are now familiar and simple truths is always a fascinating study. If 
rightly pursued it should give us a psychological insight into the mental modes 
of man. One great difficulty must ever be the imperfection of the historic 
imagination. Just as the mature intellect is apt to misinterpret the modes of 
thought of the child or savage, so we, the heirs of centuries of accumulated 
knowledge, have difficulty in appreciating the intellectual needs and powers of 
our ancestors. Where, however, as in the case before us, the mark of the stage 
of culture arrived at is a mechanical contrivance or an illustrative experiment, 
there is less play for the personal equation, there is more chance for a sound 
judgment. Doctors Gerland and Traumiiller have put together an extremely 
interesting book in which is presented, on its purely experimental side, the 
evolution of physical science from the early days of the Assyrians, Egyptians, 
and Greeks, through the times of the Middle Ages to the end of the sixteenth 
century, when with Galileo the modern school of experimental science may be 
said to have begun, and from this epoch on to our own days. Nearly a century 
before Galileo’s time, however, we find in Leonardo da Vinci—famous even in 
his own day as painter, sculptor, musician, architect, and engineer—a type of the 
true scientific spirit. Particularly fruitful were his inventions and discoveries 
in hydraulics. 
To give a fair notion of the contents of the book, suffice it to say that it 
is chiefly concerned with the invention of such familiar instruments as the 
telescope, microscope, pendulum, air-pump, thermometer, barometer, hygro- 
meter, the electric machine, voltaic cell, galvanometer, induction coil, tele- 
graph, etc. 
The cuts and illustrations are numerous and instructive. Many are 
reproduced from original sources, and some are of high interest. Perhaps the 
most curious is the picture of von Guericke’s experiment showing two teams of 
horses (sixteen in all) engaged in “‘a tug of war,” the object being to pull asunder 
two gigantic Magdeburg hemispheres within which a vacuum has been formed. 
Very instructive also are the ingenious mechanical devices employed by our 
scientific forefathers to illustrate or demonstrate important mechanical principles. 
Not a few of these might with advantage be introduced for demonstrative 
purposes in our schools and colleges. C. Gk 
POPULAR ENTOMOLOGY. 
True Tales of the Insects. By L. N. BADENOCH. 8vo, pp. xviii. + 255, with 
44 figs. London: Chapman and Hall, Ltd., 1899. Price 12s. 
Iv was a happy inspiration of the author to devote most of this handsome 
volume to insects with stories of such interest and so little hackneyed as are 
those of the Orthoptera. Though popular in aim the book bears evidence of a 
true love of entomology and of a knowledge of the creatures described that are 
far from universal in similar works ; and few readers will lay it down without 
the desire to learn more of its subject. The essays on Lepidoptera, which 
occupy the last eighty pages, are scarcely equal to the others. 
Unfortunately the literary form often leaves a good deal to be desired. 
Such sentences as these are too frequent :—“ Others again can fly, having ample 
wings, and, oddly enough, often gaily coloured. Look at the large spectre 
Acrophylla titan of Australia, a giant of its kind ; its charming wings generally 
