58 
POPULAR SCIENCE REVIEW. 
GEOMETRY.* 
T HIS work is intended for students wishing to gain such a knowledge 
of the principles of Practical Geometry as shall he useful to them in 
the drawing-office or the workshop. It contains under the heads of 
Practical Plane Geometry, and Orthographical Projection or Solid Geo- 
metry, numerous examples of the different problems arising in the study of 
geometrical drawing, the methods of solution being given with considerable 
detail, and very fully illustrated. Most of the cases are representative 
of such as have actually occurred during the author’s class-teaching, and 
a large number of the examples given for practice are selected from 
the examination papers of South Kensington and the Indian Engineer- 
ing College. A principal purpose of the work, as announced on the title- 
page, is 1 to meet the requirements of the higher stages in the Science and 
Art Department Syllabus,’ and this it is certainly well adapted to do, as 
any student who had carefully studied it might he expected to take a good 
position in the South-Kensington examinations. The excellence of the work 
for this purpose will, however, make it somewhat disappointing to those who 
may look into it for information on other than the simpler kind of knowledge 
required by elementary students ; and it may be regretted that the author 
has found it necessary to restrict his work so closely within the limits 
of the Syllabus. For example, there is practically nothing about per- 
spective projections, the only information given under this head being 
confined to a few pages on isometric projection, which is treated merely 
as resulting from a peculiar property of the cube, instead of being a repre- 
sentative, and that the least valuable one, of the class of axonometrical pro- 
jection, the more important monodimetric and anisometric kinds being not 
even mentioned by name. The statement that isometric projection is only 
applicable to rectangular solids is unfortunate, a3 one of the few useful appli- 
cations of this kind of drawing is in the delineation of the workings on 
mineral veins which are solids of more irregular curvature than any that 
it is probably ever necessary to represent in any other branch of industrial 
drawing. 
In going through a work such as the present, the question is forcibly 
presented as to how far the working of complex cases of oblique projection, 
of intersecting solids of the most irregular character, such as are presented 
in its pages, is necessary to make a good mechanical draughtsman. The 
author tells us ‘ that an ignorance of projection must be a fatal impediment 
to success in the workshops.’ This contrasts somewhat amusingly with the 
experience of one of our most scientific mechanical engineers, Prof. 
Fleeming Jenkins, F.R.S., who in his presidential address at Edinburgh, in 
1871, speaks of 1 the little quasi mechanical drawing which is taught’ 
(under the Science and Art Department scheme) ‘ as mostly mere geo- 
metrical projection, a subject of which real draughtsmen very frequently, 
and with little loss to themselves, are profoundly ignorant. Descriptive 
* Practical Plane Geometry and Projection. By Henry Angel. 8vo, with 
4to Atlas of Plates. Wm. Collins, Sons, and Co. (Limited.) London and 
Glasgow. 1880. 
