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this Hypothesis. — Improvement in a Globe for

raising the Electric Fire . . . . . . 269

E. KINNERSLEY To B. Franklin. 3 February, 1752.

New Experiments. — Paradoxes inferred from them.

- Difference in the Electricity of a Globe of Glass

charged, and a Globe of Sulphur. — Difficulty of

ascertaining which is positive and which negative 273

To E. KINNERSLEY. 2 March, 1752.

Probable Cause of the different Attractions and

Repulsions of the two Electrified Globes mentioned

in the preceding Letter . . . . . . 275

James Bowdoin to B. Franklin. 2 March, 1752.

Effect of Lightning on Captain Waddel's Compass,

and on the Dutch Church at New York . . . 276

James Bowdoin to B. FRANKLIN. 16 March, 1752.

Remarks on Dr. Colden's Letter respecting the

Electricity of the Clouds . . . . . . 279

To E. KinnERSLEY. 16. March, 1752.

Reasons for supposing that the Glass Globe charges

positively, and the Sulphur negatively. — Hint re-

specting a Leather Globe for Experiments when

travelling . . . . . . . . 280

To Cadwallader Corden. 23 April, 1752..

Mistake, that only Metals and Water were Con-

ductors, rectified. — Supposition of a Region of

Electric Fire above our Atmosphere. — Theorem

concerning Light. - Poke-weed a Cure for Cancers 283

M. DalibARD's Account of an Electrical Experiment at

Marly . . . . . . . . . . 288

ABBÉ Mazkas to Stephen HalES. 20 May, 1752.

Giving a further Account of the Electrical Experi-

ment at Marly . . . . . . . . 293

To Peter Collinson. 19 October, 1752.

Electrical Kite . . . . . . . 295

W. Watson to the Royal Society. 21 Dec. 1752.

Concerning the Electrical Experiments in England

upon Thunder-clouds . . . . . . . 296

To James Bowdoin. 12 April, 1753.

On the Mode of coating Electrical Jars . . . 299

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To Peter COLLINSON. September, 1753.

· Hypothesis of the Sea being the grand Source of

Lightning retracted. — Positive, and sometimes

negative, Electricity of the Clouds discovered. —

New Experiments and Conjectures in Support of

this Discovery. — Observations recommended for

ascertaining the Direction of the Electric Fluid. —

Size of Rods for Conductors to Buildings. — Ap-

pearance of a Thunder-cloud described . . . 300

To Peter COLLINSON. 23 November, 1753.

Notice of another Packet of Letters . . . 314

Proposal of an Experiment to measure the Time taken

up by an Electric Spark in moving through any

given Space. By James Alexander, of New York 315

Answer to the Foregoing . . . . . . . 317

Remarks on the Abbé Nollet's Letters to Benjamin

Franklin on Electricity. By David Colden, of

New York. 4 December, 1753 . . . 319

Electrical Experiments, with an Attempt to account for

their several Phenomena. Together with some

Observations on Thunder-clouds, in further Confirm-

ation of Mr. Franklin's Observations on the Posi-

tive and Negative Electrical State of the Clouds.

By John Canton. 6 December, 1753. . . 330

To James Bowdoin. 13 December, 1753.

Concerning the Light emitted by Salt Water. -

The Abbé Nollet's Letters on Electricity . . 337

To Peter CollinsON. 18 April, 1754.

Additional Proofs of the Positive and Negative

State of Electricity in the Clouds. — New Method

of ascertaining it . . . . . . . 340

Experiments made in Pursuance of those made by Mr.

Canton, dated December 6th, 1753 ; with Explan-

ations, by Benjamin Franklin. 14 March, 1755 341

Turkey killed by Electricity. – Effect of a Shock on

the Operator in making the Experiment . . 346

To John Lining. 18 March, 1755.

Differences in the Qualities of Glass. — Account

VOL. V.

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