il 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 WiLuterr LEPLEY 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 : 
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 
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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. 
THOMPSON—Light Visible and Invisible. | SUTER-—-Handbook of Optics. For Stu- 
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 WOOD SuTER, M.D., Professor of Ophthalmology, 
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the usual text-books on Refraction of the Eye. 
LANGE—Our Native Birds. How To PRro- 
TECT THEM AND ATTRACT THEM TO OUR HOMES. 
By D. LANGE, Instructor in Nature Study in the 
Schools of St. Paul, Minn., author of a ‘‘ Manual 
BURBURY—A Treatise on the Kinetic 
Theory of Gases. By S. H. BurBuRy, M.A., 
F.R.S., late Fellow of St. Johns, Cambridge. 
8vo, Cloth. Price, $2.00 net. 
Cambridge University Press. of Nature Study.” Cloth, 12mo. Nearly Ready. 
AREY — Elementary Chemistry. For HicH | | ENGFELD—Inorganic Chemical Prepa= 
SCHOOLS AND ACADEMIES. By A. L. AREY, rations. By FreLrx LENGFELD, Assistant Pro- 
Teacher of Chemistry and Physics in the High fessor of Inorganic Chemistry in the University of 
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' oa, Wen, Menai Lary. This book gives directions for making about fifty 
This book is designed to fully prepare students for | substances, and is intended for college students with 
entrance to the leading universities. some knowledge of analytical chemistry. 
Blowpipe Analysis 
By FREDERICK HuTTON 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. 
