SOUNDING THE OCEAN OF AIR

BEING SIX LECTURES DELIVERED BEFORE THE LOWELL INSTITUTE OF BOSTON IN DECEMBER 1898

BY

A. LAWRENCE ROTCH, S.B., A.M.,

DIRECTOR OF THE BLUE HILL METEOROLOGICAL OBSERVATORY, MASSACHUSETTS, U.S.A., AND MEMBER OF THE INTERNATIONAL CLOUD AND AERONAUTICAL COMMITTEES. PUBLISHED UNDER THE DIRECTION OF THE GENERAL LITERATURE COMMITTEE.

LONDON: SOCIETY FOR PROMOTING CHRISTIAN KNOWLEDGE, NORTHUMBERLAND AVENUE, W.C.; 43, QUEEN VICTORIA STREET, E.C. Brighton: 129, North Street. New York: E. & J. B. YOUNG & CO. 1900

This little Book is gratefully Dedicated TO The late AUGUSTUS LOWELL, Esq. OF BOSTON, U.S.A. WHO, AS TRUSTEE OF THE LOWELL INSTITUTE, ENABLED SCIENTIFIC MEN OF TWO CONTINENTS TO PRESENT THE RESULTS OF THEIR INVESTIGATIONS TO THE PUBLIC

CORRIGENDA

Page 50, line 11, for "isolation" read "insolation." Page 59, line 21, before "direction" insert "opposite." Page 112, line 2; page 115, lines 2 and 15, and Index, pages 175 and 183, for "Viollé" read "Violle." Page 112, line 23; page 113, line 6, and Index, page 181, for "Muntz" read "Müntz." Page 123, last line, for "1889" read "1891." Index, page 177, for "Cotte (T.)" read "Cotte (L.)." Index, page 179, after "Hann (J.), 36," add "173." Index, page 179, for "Hellman (G.)" read "Hellmann (G.)." Index, page 181, after "Langley (S. P.)" insert "28."

[Transcriber's Note: These corrections have been applied to the current version]

CONTENTS

CHAP. PAGE

I. THE ATMOSPHERE—ANCIENT AND MODERN KNOWLEDGE—METHODS OF INVESTIGATION9

II. CLOUDS—FORMATION AND CLASSIFICATION—MEASUREMENTS AT BLUE HILL—THE INTERNATIONAL OBSERVATIONS38

III. BALLOONS—NOTABLE ASCENTS AND RESULTS OBTAINED—CAPTIVE BALLOONS68

IV. BALLONS-SONDES FOR GREAT ALTITUDES—THE INTERNATIONAL ASCENTS98

V. KITES—HISTORY AND APPLICATION TO METEOROLOGICAL PURPOSES AT BLUE HILL AND ELSEWHERE117

VI. RESULTS OF THE KITE-FLIGHTS AT BLUE HILL—FUTURE WORK145

INDEX175

LIST OF ILLUSTRATIONS

PAGE

Plate I.Comparative Altitudes22

Plate II.Optical Phenomena showing the Height of the Atmosphere26

Plate III.Temperature at different Latitudes and Altitudes31

Fig. 1.Nephoscope at Blue Hill Observatory.52

Fig. 2.Cloud Theodolite at Blue Hill Observatory54

Plate IV.Heights and Velocities of Clouds57

Plate V.Atmospheric Circulation at different Heights in Cyclones and Anti-cyclones61

Fig. 3.German Balloon equipped for Meteorological Observations87

Plate VI.Temperatures observed in Four High Balloon Ascents 91

Fig. 4.German Kite-balloon.95

Fig. 5.Baro-thermograph of Richard102

Fig. 6.The Aérophile rising103

Plate VII.Heights and Temperatures recorded in eight Ascents of the Cirrus109

Fig. 7.Oriental tailless Kites.119

Fig. 8.Eddy tailless Kite129

Fig. 9.Hargrave Kite130

Fig. 10.Modified Hargrave Kites at Blue Hill133

Fig. 11.Lamson's Aero-curve Kite135

Fig. 12.Meteorograph lifted by Kites at Blue Hill138

Plate VIII.Meteorogram from the Kite-flight of Oct. 8, 1896, at Blue Hill 148

Plate IX.Mean Changes with Height, and Changes during the Kite-flight of Oct. 8, 1896150

Plate X.Changes with Height recorded by Kites at Blue Hill155

Plate XI.Kite Observations at Blue Hill, Sept. 5-11, 1897163

Plate XII.Automatic Records during a High Kite-flight at Blue Hill166

Plate XIII.Results of Kite-flights at Blue Hill during an Anti-cyclone and a Cyclone168

SOUNDING THE OCEAN OF AIR