il SCIENCE.—ADVERTISEMEN'S. 
NEW CHEMICAL WORKS-—Just Ready or in Press 
The Liquefaction of Gases 
Just Ready. Its RisE AND DEVELOPMENT. Cloth, 12mo, $1.50. 
By Wittetr LeEPLEY HARDIN, Harrison Senior Fellow in Chemistry in the University of Penn- 
sylvania. 
A complete history of the development of the methods employed in the liquefac- 
tion of gases, as the following clipping from the preface will show : 
Recent “Recent developments in the liquefaction of air and the recent liquefaction of hydro- 
Developments _ gen have added considerable interest to the whole subject of the liquefaction of gases. 
The literature on this subject is scattered, for the most part, in foreign journals, and is 
inaccessible to a majority of those who are interested in scientific work. 
Scope of “The object of this little volume is to present a complete history of the development 
the Book of the methods employed in the liquefaction of gases. Sufficient theory has been given to 
enable the popular reader to understand the principles involved. While the book has been 
written in a popular-science style, an effort has been made to make it of value to those who 
are especially interested in the subject by giving the references to the original literature.’’ 
Industrial The various forms of apparatus are shown in illustrations. In addition to the history 
Application of the development of the methods, the condition of matter at the critical point, the theory 
of the gaseous and liquid states of matter, and the theory of the regenerative method of 
refrigeration are also considered. In the conclusion, a brief outline is given of researches 
at low temperatures and of the industrial application of liquefied gases. 
OF A MORE ELEMENTARY CHARACTER ARE 
Elementary Chemistry 
For HiguH SCHOOLS AND ACADEMIES. 
By A. L. Arty, Teacher of Chemistry and Phys- 
ics in the High School, Rochester, N. Y. 
Cloth, 12mo. Ready in September. 
This book is designed to fully prepare students for 
entrance to the leading universities. It will serve 
both as a laboratory manual and asa text-book. The 
portion of the work introducing qualitative analysis 
is usually complete, yet only simple experiments and 
such tests as are not too difficult for high school pu- 
pils are employed. The book is thoroughly abreast of 
the times in its description of recent discoveries and 
inventions. 
Inorganic Chemical Preparations 
By Frevtix LENGFELD, Assistant Professor of 
Inorganic Chemistry in the University of 
Chicago. Cloth, 16mo. Ready in September. 
This book gives directions for making about fifty 
substances, and is intended for college students with 
some knowledge of analytical chemistry. The course 
will serve as a review in general chemistry, and in- 
cludes some preparations with which the ordinary 
student is familiar, others which he usually known 
only by name, the arrangement being according to 
the scale of increasing difficulty. Copious references. 
to the literature of the subject are given and will be 
found useful to both student and instructor. 
Blowpipe Analysis 
By FrepERIcK Hurron GETMAN, Instructor in Chemistry in Stamford High School. 
16mo. Ready in September. 
Cloth, 
This little book is designed for use in high schools, and also to serve as an aid to college students in 
the study of qualitative analysis. 
THE MACMILLAN COMPANY, Publishers, New York. 
