380 Bihliography. 



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 cannot 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 present 

 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 naeeting of the Association in August, 1843. 



2. Perkinses 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 ; 

 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- 

 mula for the answer, would at once find mysteries dissolved about him, 

 and his labor changed into an exciting pastime. 



Mr. Perkins has addressed himself to teaching algebra in its purity, 

 and has skillfully carried his pupil through the successive stages of the 

 science to equations of the higher degrees, and the methods of treating 

 them generally, not omitting the theorem of Sturm 



