238 RECORD OF THE ROYAL SOCIETY 



3. Huygens's Aerial Telescope. 



(1) An Object-glass of 122 feet focal length, with an eye- 



glass of 6 inches, and original apparatus for adjust- 

 ment, made by Huygens, and presented by him to the 

 Royal Society in 1691. 



(2) The apparatus for using Huygens's object-glass, con- ^ 12 parts. 



structed by Hooke. 



(3) Additional apparatus, by Dr. Pound. Presented by Dr. 



Bradley. 



(4) Ditto, by Mr. Cavendish. 



4. An Object-glass by Huygens, of 170 feet focal length. Presented to the 



Royal Society by Sir Isaac Newton, P.R.S. 



5. An Object-glass by Huygens, with two eye-glasses by Scarlet, for a 



Telescope of 210 feet. Presented by the Rev. Gilbert Burnet, M.A., 

 F.R.S., in 1724. 



6. An Object-glass (Venetian), of 90 feet focal length : which belonged to 



Flamsteed. Presented to the Royal Society by James Hodgson, F.R.S., 

 in 1737. 



7. Chronometer, by Arnold. 



8. Chronometer, by Arnold. 



Both these Chronometers accompanied Captain Cook on his second and third 

 Voyages. 



9. Armed Loadstone. 



Grew's c Catalogue of Rarities ' (p. 364) mentions an Orbicular Loadstone or Ter- 

 [r]ella, given by Sir Christopher Wren, the size of which, so far as the stone is 

 concerned, agrees with the above ; it is conjectured that it may be the same. 



10. A Galvanic Battery, made by Dr. Wollaston, in a tailor's thimble. 



Presented to the Royal Society by Sir A. W. Franks, June 28, 1879. 

 In a letter to the late William Spottiswoode, P.R.S., which accompanied this 

 present, Sir (then Mr.) Augustus Wollaston Franks says that this little battery 

 was given by his godfather, Dr. Wollaston, to his mother, then Miss Sebright. 

 See also an anecdote about this battery in Weld's ' History of the Royal Society', 

 vol. 2, p. 309. 



11. Dr. Priestley's Electrical Machine. 



12. The original Model for Davy's Safety Lamp. 



13. The Mountain Barometer used by the late Mr. Charles Darwin, F.R.S., 



during his voyage round the world in H.M.S. * Beagle '. Presented by 

 his executors in December, 1899. 



14. A case of radiometers and otheoscopes used by Sir William Crookes to 



illustrate his papers read before the Society between 1875 and 1878 in 

 connexion with his researches on 'Repulsion Resulting from Radiation'. 

 Presented by Sir William Crookes, For.Sec.R.S., October, 1911. 

 The remainder of the instruments lately in the possession of the Society 

 have been deposited in the Science Museum, South Kensington. 



