li SCIENCE.—ADVERTISEMENTS. 
NEW SCIENTIFIC BOOKS—Just Ready or in Press 
The Liquefaction of Gases 
Just Ready. Irs RIsE AND DEVELOPMENT. Cloth, 12mo, $1.50. 
By Witterr LepLey Harbin, 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 : 
Popular ‘Recent developments in the liquefaction of air and the recent liquéfaction 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- 
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 principlesinvolved. 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. 
THOMPSON—Light Visible and Invisible. | SUTER—Handbook of Optics. For Srvu- 
A Series of Popular Lectures delivered by SYLVA DENTS OF OPHTHALMOLOGY. By WILLIAM NOR- 
Nus P. THompson, D.Sc., M.R.I., F.R.S., author 
of ‘‘Elementary Lessons in Electricity and Mag- 
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“Popular and extremely interesting from begin- 
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“Reliable and up-to-date . . . of great value to 
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BURBURY—A Treatise on the Kinetic 
Theory of Gases. By S. H. Burspury, M.A., 
F.R.S., late Fellow of St. Johns, Cambridge. 
8vo, Cloth. Price, $2.00 net. 
Cambridge University Press. 
AREY —Elementary Chemistry. For Hicu 
ScHOOLS AND ACADEMIES. By A. L. AREY, 
Teacher of Chemistry and Physics in the High 
School, Rochester, N. Y. 
Cloth, 12mo0. Nearly Ready. 
This book is designed to fully prepare students for 
entrance to the leading universities. 
WOOD SuTER, M.D., Professor of Ophthalmology, 
National University, and Assistant Surgeon, Epis- 
copal Eye, Ear and Throat Hospital, Washington, 
D.C. Cloth, 16mo, $1.00 net. 
The object of this book is to give the student a 
clearer insight into the phenomena of refraction as: 
applied to ophthalmology than can be obtained from 
the usual text-books on Refraction of the Hye. 
LANGE—Our Native Birds. How To Pro- 
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By D. LANGE, Instructor in Nature Study in the 
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of Nature Study.” Cloth, 12mo0. Nearly Ready. 
LENGFELD—Inorganic Chemical Prepa= 
rations. By FrLix LENGFELD, Assistant Pro- 
fessor of Inorganic Chemistry in the University of 
Chicago. Cloth, 16mo, 60 cents nef. 
This book gives directions for making about fifty 
substances, and is intended for college students with 
some knowledge of analytical chemistry. 
Blowpipe Analysis 
By Freperick HuTron GrErman, 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. 
