i SCIENCE. ADVERTISEMENTS. 
NEW SCIENTIFIC BOOKS—Just Ready or in Press 
The Liquefaction of Gases 
Just Ready. Its RIsE AND DEVELOPMENT. Cloth, 12mo, $1.50. 
By Witterr LepLey Harp, Harrison Senior Fellow in Chemistry in the University of Penn- 
sylvania. i 
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 : 
Popular ‘* Recent developments in the liquefaction of air and the recent liquefaction of hydro- 
Up-to-date 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 
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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 
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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. 
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MACBRIDE—The Slime Moulds. A HAnp- 
The object of this book is to give the student a 
BOOK OF NORTH AMERICAN SLIME MouLps. By 
THoMAS H. MAcBRIDE, Professor of Botany, Uni- 
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A list of all species described in North America, 
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AREY —Elementary Chemistry. For Hicu 
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Teacher of Chemistry and Physics in the High 
School, Rochester, N. Y. 
Cloth, 12mo. Nearly Ready. 
This book is designed to fully prepare students for 
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LANGE—Our Native Birds. How To Pro- 
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LENGFELD—Inorganic Chemical Prepa= 
rations. By FELIX LENGFELD, Assistant Pro- 
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This book gives directions for making about fifty 
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Blowpipe Analysis 
By FREDERICK HuTron GETMAN, Instructor in Chemistry in Stamford High School. Cloth, 
16mo. Just Ready. 60 cents net. 
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. 
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