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Miscellaneous Intelligence. - 149 
Warren, C.E., Professor of Descriptive Geometry and Geometrical 
Drawing in the Rensselaer Polytechnic ete: — N. Y., 412 pp., 
8vo. New York: Joun Witry, 1860.—This is a more extended work 
than any other. American ones on Deaviptive Genlaniane which has 
hitherto appeared. It is rigorously systematic and truly philosophical 
in its general plan, but is open to the objection of being encumbered 
with a complex system of divisions, and subdivisions in a descending 
scale, that will not be apprehended readily by the student. Notwith- 
standing this objection, the work is on the whole admirably adapted to 
secure the important educational benefits to be derived from such a study 
—the realization of a 0% mental culture, as well as the acquisition of 
exact know ledge. m this point of view the most striking feature is 
the plan of vided is tiie detailed solution of each problem, an out- 
line sketch of the process, sive en without reference to a diagram, which 
the author saat mien a “ Solution in Space.’ gee eon feature 
of treatment of some of these topics the author has iistiapeaa consider- 
able originality. The doctrine of tangency especially is presented in a 
new light. A new definition is given of a tangent line not liable to cer- 
tain plausible objections that may be urged against the definition gener- 
ally adopted, and which may be more readily and more distinctly appre- 
hended by the student, and conducts more readily to the rules for draw- 
ing tangents to special curves. But if the author desires that the defi- 
oo extended for use in the pa m. We have, aces Ae 
doubt that it will find its way into the library of students: who are ambi- 
rati in rime recomposition tion of 
: ete the whole of the first two Scat the whole is enriched by 
_ humerous additions, designed to make it an exact and useful manual for 
© teacher as well as for the student. 
