arising from Experiments and Observations made

at Philadelphia, 1749.- Golden Fish.-Extrac-

tion of Effluvial Virtues by Electricity impracticable 227

Additional Experiments; proving that the Leyden Bot-

tle has no more Electrical Fire in it when charged,

than before; nor less when discharged; that, in

discharging, the Fire does not issue from the Wire

and the Coating at the same Time, as some have

thought, but that the Coating always receives what

is discharged by the Wire, or an equal Quantity;

the outer surface being always in a Negative State

of Electricity, when the inner Surface is in a Posi-

tive State

TO JAMES BOWDOIN, AT BOSTON. 25 October, 1750.

Enclosing Papers on Electricity

To A FRIEND IN BOSTON. 25 December, 1750.

Account of an Accident while making an Electrical

Experiment

To JAMES BOWDOIN. 5 September, 1751.

Introducing Mr. Kinnersley as a Lecturer on Elec-

Unlimited Nature of the Electric Force

Queries and Answers referred to in the foregoing Letter.

The Terms "Electric per se

-

253

255

255

257

258

259

" and "Non-elec-

tric" improper. - New Relation between Metals

and Water. Effects of Air in Electrical Experi-

ments. Experiment for discovering more of the

Qualities of the Electric Fluid .

JAMES BOWDOIN TO B. FRANKLIN. 21 Dec. 1751.

On the Causes of the crooked Direction of Light-

ning. Objections to the Hypothesis that the Sea

is the Source of Lightning. On the Swiftness of

the Electrical Fire

To JAMES BOWDOIN. 24 January, 1752.

Observations on the Subjects of the preceding Let-

ter. Reasons for supposing the Sea to be the

grand Source of Lightning.—Reasons for doubting

263

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

To E. KINNERSLEY. 2 March, 1752.

Probable Cause of the different Attractions and

Repulsions of the two Electrified Globes mentioned

in the preceding Letter

JAMES BOWDOIN TO B. FRANKLIN. 2 March, 1752.

Effect of Lightning on Captain Waddel's Compass,

and on the Dutch Church at New York.

273

275

276

JAMES BOWDOIN TO B. FRANKLIN. 16 March, 1752.

Remarks on Dr. Colden's Letter respecting the

Electricity of the Clouds

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

.

279

280

To CADWALLADER COLDEN. 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

ABBÉ MAZEAS TO STEPHEN HALES. 20 May, 1752.

Giving a further Account of the Electrical Experi-

W. WATSON TO THE ROYAL SOCIETY. 21 Dec. 1752.

Concerning the Electrical Experiments in England

upon Thunder-clouds

To JAMES BOWDOIN. 12 April, 1753.

On the Mode of coating Electrical Jars

288

293

296

299

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 .

-

TO PETER COLLINSON. 23 November, 1753.

Notice of another Packet of Letters

300

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

317

Answer to the Foregoing

Remarks on the Abbé Nollet's Letters to Benjamin

Franklin on Electricity. By David Colden, of

New York. 4 December, 1753

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

To JAMES BOWDOIN. 13 December, 1753.

Concerning the Light emitted by Salt Water.

The Abbé Nollet's Letters on Electricity

New Method

319

330

337

To PETER COLLINSON. 18 April, 1754.

Additional Proofs of the Positive and Negative

State of Electricity in the Clouds.

of ascertaining it

Experiments made in Pursuance of those made by Mr.

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

ations, by Benjamin Franklin. 14 March, 1755.

Turkey killed by Electricity.-Effect of a Shock on

the Operator in making the Experiment

TO JOHN LINING. 18 March, 1755.

-

Con

of Domien, an Electrician and Traveller.

jectures respecting the Pores of Glass.-Origin of

the Author's Idea of drawing down Lightning. -

No satisfactory Hypothesis respecting the Manner

in which Clouds become electrified. - Six Men

knocked down at once by an Electrical Shock.

Reflections on the Spirit of Invention

To M. DALIBARD. 29 June, 1755.

-

-

Beccaria's Work on Electricity.- Sentiments of

Franklin on pointed Rods, not fully understood in

Europe. Effect of Lightning on the Church of

Newbury, in New England. - Remarks on the

Subject

-

To JOHN PRINGLE. 21 December, 1757.

347

355

On the Effects of Electricity in Paralytic Cases 359

To THOMAS HUBBARD. 28 April, 1758.

Electrical Apparatus.- Description of a Battery. 361

TO WILLIAM HEBERDEN. 7 June, 1759.

On the Electricity of the Tourmalin

-

E. KINNERSLEY TO B. FRANKLIN. 12 March, 1761.

Experiments on boiling Water, and Glass heated by

boiling Water. Doctrine of Repulsion in elec-

trized Bodies doubted. Electricity of the Atmo-

sphere at different Heights. Electrical Horse-

Electrical Thermometer. In what Cases

the Electrical Fire produces Heat.- Wire length-

race.

-

- -

-

ened by Electricity. Good Effect of a Rod on

-

the House of Mr. West, of Philadelphia .

To E. KINNERSLEY. 20 February, 1762.

Answer to some of the foregoing Subjects. - How

long the Leyden Bottle may be kept charged.-

Heated Glass rendered permeable by the Electric

Fluid. Electrical Attraction and Repulsion.-

Reply to other Subjects in the preceding Paper.

Numerous Ways of kindling Fire. — Explosion of

Water.- Knobs and Points

Accounts from Carolina (mentioned in the foregoing

Letter) of the Effects of Lightning on two of the

367

378

Rods commonly affixed to Houses there, for secur-

-ing them against Lightning. 1 November, 1760 . 395

Mr. William Maine's Account of the Effects of the

Lightning on his Rod, dated at Indian Land, in

South Carolina, August 28th, 1760..

Remarks by Benjamin Franklin

To MISS MARY STEVENSON. 22 March, 1762.

Concerning the Leyden Bottle

Electrical Experiments on Amber. 3 July, 1762 .

JOHN WINTHROP TO B. FRANKLIN. 29 Sept., 1762.

New Observation relating to Electricity in the At-

mosphere

ALEXANDER SMALL TO B. FRANKLIN.

396

403

405

TO THOMAS RONAYNE. 20 April, 1766.

On the Electricity of the Fogs in Ireland

Mode of ascertaining whether the Power, giving a Shock

to those who touch either the Surinam Eel or the

Torpedo, be Electrical

Addition, 12 August, 1772, in Consequence of the Ex-

periments and Discoveries made in France by Mr.

Walsh, and communicated by him to Dr. Franklin

Of Lightning, and the Methods (now used in America)

of securing Buildings and Persons from its mis-

chievous Effects. September, 1767

JOHN WINTHROP TO B. FRANKLIN. 6 January, 1768.

St. Bride's Steeple

TO JOHN WINTHROP. 2 July, 1768.

On Conductors for protecting Houses from Light-

ning. Singular Kind of Glass Tube

E. KINNERSLEY TO B. FRANKLIN.

407

409

412

413

414

419

419

13 October, 1770.