380 Bibliography. 
mainly from the researches of Prof. Liebig and his numerous pupils in 
the laboratory of Giessen ; although the labors of other chemists have 
also contributed to the result. 
The views of Prof. Liebig, founded on the incontrovertible evidences 
of numerous analyses, cannot be gainsayed ; and one of the most valu- 
able features of the book is its suggestive character, showing us the 
importance of observations comparatively trivial when connected with 
the development of important truth. We camnot in our present limits 
give any notion of the mode in which a great variety of important 
topics, involving the whole province of animal and vegetable physiol- 
ogy, and the laws of vital energy, are discussed. Every one, whether 
scientific or not, who feels the least interest in the progress of knowl- 
edge, will read this book with pleasure and profit; while all who are 
engaged in similar pursuits must make it a constant study. — It is a most 
lucid condensation of the results of years of laborious research, not of 
the author only, but of all his contemporaries. 
This is the second part of the report on the progress and viedo : 
condition of organic chemistry, drawn up by Prof. Liebig at the instance 
of the British Association; the first part, being the organic chemistry 
of agriculture, &c., and the third and concluding part, will be present- 
ed at the next meeting of the Association in August, 1843. 
SO Perkins Algebra.—The author of this work, already favorably 
made known by his “ Higher Arithmetic,” has brought to the task of 
preparing a manual of algebra the experience of both teacher and 
editor. He evinces a just conception of the utility of early training 
the learner in strict symbolic algebra, and holding his mind fast to the 
contemplation of letters or general signs, in preference to relaxing into 
numerical terms and coefficients. The three elemental branches of 
mathematics—arithmetic, algebra, and geometry, are separated by dis- 
tinct outlines, and each should be studied by itself as a perfect system. 
The clearest ideas of geometrical demonstrations, are those which have 
no associations with algebraic statements of proportions or equations 5 
and the most luminous and satisfactory processes in algebra, are those 
which are least encumbered with arithmetical numerals. Many a stu- — 
dent toils through equations, working mainly by mere numerals, with- 
out obtaining any definite notion of the power and certainty of algebra, 
who, if taught to replace numerals by letters and always frame a for- 
taula for the answer, would at once find mysteries. dissolved about him, 
Mr. Perkins: himself to teaching slgobre ints pity, 
2a. and has ski i eassica his pupil through the successive stages of the 
| seienee to equations of the higher degrees, and the methods of treating 
a . theorem of Sturm 
i 
5 ae: > 
