REVIEWS. 
417 
practical ; and tlie u Diamond Mines of South Africa ” are well described by 
Mr. Francis Oats, who for some years occupied the position of Provincial 
Mining Engineer at Kimberley. Mr. Robert Oxland, of Plymouth, furnishes 
a description of his rotating calciner for sulphurous and arsenical ores ; and 
Mr. Thomas Andrews, of Edinburgh, gives an article upon the “ Mineral 
Oils used for Lighting Purposes.” 
The shorter notices have been carefully prepared, and supply information 
upon such recent discoveries as the telephone and phonograph. The Supple- 
ment to “ Ure’s Dictionary ” is in every way worthy of the original work, and 
will form a valuable addition to the library of the miner, manufacturer, and 
metallurgist. 
THE SIGHT.* 
D R. ANGELL’S little book on “ The Sight ” is intended by its author to dif- 
fuse generally a knowledge of the phenomena of vision, and to furnish 
the public with reliable information as to the means to be adopted for the 
preservation of the faculty of sight. In face of the increasing prevalence of 
weak sight among us, it must be confessed that this object is a most important 
one, and we can only express a hope (not a very sanguine one, however) that it 
may satisfy the author’s aspirations. If it fails, it will not be his fault, as 
his book is certainly one of the best adapted to its purpose that we have 
seen. The use of technical language is avoided as much as possible. 
Dr. Angell furnishes his readers with a short description of the structure 
of the eye, so as to explain how we see, and what are the causes of defective 
vision. He then proceeds to the discussion of the various kinds of defective 
vision, their causes and remedies, or at all events the best modes of ameliorating 
those defects of vision which steal upon us in consequence of increasing years 
or failure of the eye at an earlier age. His remarks upon near sight in chil- 
dren and young people and its causes are of great importance. 
There are one or two points to which we may refer. — At page 42 the 
author says that u twenty-five men in every hundred are more or less colour- 
blind : they cannot distinguish red from green.” This ratio is much higher 
than is generally admitted, though perhaps very slight degrees of colour- 
blindness may occur in such proportions. On page 29, line 22, the eye in near 
sight is said to be “ adjusted or accommodated” for a point nearer than the 
object looked at ; the use of these two terms is unfortunate, as they are tech- 
nically used to signify the change in the refractive state of the eye brought 
about by muscular action. The refractive state of the eyeball in near sight 
is dependent on the construction of its media, and would continue in a dead 
eye if this preserved its shape and clearness. The true sense of accommoda- 
tion is given by the author at page 12, but it might easily escape the memory 
of a reader interested only in near sight. These and one or two other small 
matters which might be cavilled at are, however, of little consequence, and 
we may recommend Dr. Angell’s book as a very clear and comprehensive 
treatise on the management of the eyes. It is freely illustrated. 
* 11 The Sight and Howto Preserve It.” — By Henry C. Angell, M.D., Pro- 
fessor of Ophthalmology at Boston University, sm. 8vo., London : Hardwicke 
and Bogue, 1878. 
NEW SERIES, YOL. IT.- — NO. VIII. E E 
