Entered according to the act of Congress, in the year one thousand eight hundred and thirty-eight, by HILLIARD, GRAY, AND CO., in the Clerk's Office of the District Court of the District of Massachusetts.

NOX

NEW YORK

CAMBRIDGE:

STEREOTYPED AND PRINTED BY

FOLSOM, WELLS, AND THURSTON,
PRINTERS TO THE UNIVERSITY.

CONTENTS

OF

VOLUME SIXTH.

LETTERS AND PAPERS ON PHILOSOPHICAL SUBJECTS.

Causes of Earthquakes. 15 December, 1737

A Proposal for promoting Useful Knowledge among the

British Plantations in America. 14 May, 1743 .

CADWALLADER COLDEN TO B. FRANKLIN. October, 1743.

A New Method of Printing

TO CADWALLADER COLDEN. 4 November, 1743

CADWALLADER COLDEN TO W. STRAHAN. Nov. 1743.

Remarks on a New Method of Printing.

TO CADWALLADER COLDEN. 5 April, 1744.

Organization of a Philosophical Society

WILLIAM STRAHAN TO C. COLDEN. 9 May, 1744.

Objections to the proposed New Method of Printing

CADWALLADER COLDEN TO B. FRANKLIN. Dec. 1744.

Concerning Thoughts on different Species of Mat-

ter. Suggestion for publishing Philosophical Pa-

pers

Page

1

.

An Account of the new-invented Pennsylvanian Fire-places

To CADWALLADER COLDEN. 15 August, 1745.

14

18

25

26

28

29

32

34

On Perspiration and Absorption.- Motion of the

Blood in the Heart

65

To CADWALLADER COLDEN. 28 November, 1745.

On the Circulation of the Blood. - Proposal for

publishing a Philosophical Miscellany

70

To CADWALLADER COLDEN.

Conjecture as to the Cause why Ships in crossing

the Atlantic have longer Passages in sailing west-

ward than in sailing eastward.

CADWALLADER COLDEN TO B. FRANKLIN.

Answer to the foregoing Letter respecting the

Sailing of Ships across the Atlantic

TO JARED ELIOT. 16 July, 1747.

Linseed Oil. Northeast Storms.

74

76

Origin of

Springs in Mountains. Petrified Shells in the

Appalachian Mountains.- Observations on a Tariff

Law

TO JARED ELIOT.

79

Experiments in the Culture of Grass in Meadows 83

TO THOMAS HOPKINSON. 1747.

On the Vis Inertia of Matter

To CADWALLADER COLDEN. 6 August, 1747.

-

Baxter's Book on the Vis Inertia of Matter.-

Manufacture of Electrical Apparatus. Colden's

Philosophical Treatise

A Conjecture as to the Cause of the Heat of the Blood

in Health, and of the Cold and Hot Fits of some

87

93

97

100

104

Northeast Storms begin at the South. Account

-

of a Copper Mine.-Subscriptions for an Acad-

emy in Philadelphia

CADWALLADER COLDEN TO B. FRANKLIN. 20 May, 1752.

Concerning Theories of Light

JOHN PERKINS TO B. FRANKLIN. 3 August, 1752.

Respecting the Number of Deaths in Boston by

TO JOHN PERKINS. 13 August, 1752.

Concerning the Smallpox in Philadelphia

114

118

To CADWALLADER COLDEN. 14 September, 1752.

Remarks on Mr. Colden's Theory of Light.

Translation of Electrical Papers into French - . 121

CADWALLADER COLDEN TO B. FRANKLIN. 24 Oct. 1752.

Cause of the Cohesion of the Particles of Matter.

Concerning a Translation of a German Writer's Re-

marks on Mr. Colden's Philosophical Principles

Physical and Meteorological Observations, Conjectures, and

123

Suppositions

127

JOHN PERKINS TO B. FRANKLIN. 16 October, 1752.

On Water-Spouts

136

JOHN PERKINS TO B. FRANKLIN. 23 October, 1752.

Further Remarks on Water-Spouts

138

W. MERCER TO B. FRANKLIN. 11 November, 1752.

Description of a Water-Spout at Antigua

143

TO JOHN PERKINS. 4 February, 1753.

Water-Spouts and Whirlwinds compared

TO JAMES BOWDOIN. 28 February, 1753.

Relating to the Transit of Mercury in 1753

TO JARED ELIOT. 12 April, 1753.

Properties of Water.

Writings in France

JOHN PERKINS TO B. FRANKLIN.

Shooting Stars

Notice of the Author's

JOHN PERKINS TO B. FRANKLIN.

164

Water-Spouts and Whirlwinds .

Observations on the Meteorological Paper; by a Gentleman

Observations in Answer to the Foregoing; by B. Franklin

171

174

VOL. VI.

A*

Observations on the Meteorological Paper; sent by Cad-

wallader Colden to B. Franklin

177

183

Answer to the foregoing Observations; by B. Franklin. 180

Extracts from Dampier's Voyages, relating to Water-Spouts

WILLIAM SHERVINGTON TO B. FRANKLIN. 20 June, 1753.

On the Transit of Mercury across the Sun, May

6th, 1753, observed at Antigua

TO THOMAS CLAP. 8 November, 1753.

On Smeaton's Air-Pump

JAMES BOWDOIN TO B. FRANKLIN. 12 November, 1753.

Concerning the Light in Sea-Water

M. DALIBARD TO B. FRANKLIN. 31 March, 1754.

Intelligence on Philosophical Subjects

-

CADWALLADER COLDEN TO B. FRANKLIN. 2 April, 1754.

Water-Spouts. Wind generated by Fermenta-

tion.- Winds blowing in contrary Directions

CADWALLADER COLDEN TO B. FRANKLIN. 2 April, 1754.

New Theory of the Motion of the Planets best

suited for calculating Astronomical Tables.-Abbé

Nollet's Book

CADWALLADER COLDEN TO P. COLLINSON. 28 May, 1754.

187

195

197

199

Account of a Whirlwind in Maryland

201

TO JOHN LINING. 14 April, 1757.

On Cold produced by Evaporation

203

JOHN BARTRAM TO B. FRANKLIN. 12 November, 1757.

Experiment with Ether for producing Cold by

Evaporation.-Water kept cool in hot Countries.

-The human Body cooled by Evaporation.-

The Surface of the Earth and Vegetation cooled

in the same Manner