APPENDIX 



Petty's Double-bottom'd ship ; it was resolved, that the 

 publication of them should be differed, till his Ma ty had been 

 made acquainted with the particulars therein, relating to 

 the said ship." Council Minutes, April 26, 1665. 

 Huygens's Aerial Telescope. 



(i) An Object-glass of 22 feet focal length,^ 

 with an eye-glass of 6 inches, and original apparatus 

 for adjustment, made by Huygens, and presented 

 by him to the Royal Society in 1691. 



(2) The apparatus for using Huygens's object- 



12 parts. 



glass, constructed by Hooke. 



(3) Additional apparatus, by Dr. Pound. Pre- 

 sented by Dr. Bradley. 



(4) Ditto, by Mr. Cavendish. 



4. An Object-glass by Huygens, of 170 feet focal length. Pre- 

 sented to the Royal Society by Sir Isaac Newton, P.RS. 



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. Convertible Pendulum of Captain Kater ; with the Agate 

 Planes. 



The basis of the present system of British Weights and 

 Measures. Phil. Trans., 1818, p. 37. 



8. Chronometer, by Arnold. 



9. Chronometer, by Arnold. 



Both these Chronometers accompanied Captain Cook on 

 his second and third Voyages. 



10. Armed Loadstone. 



Grew's 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, 

 130 



