1822.] Fhilosophical Transactions for 1821, Part II, 61 



pension ; and it is sufficiently obvious that no change can take 

 place in the length of the pendulum, but such as may arise from 

 a variation in temperature.' " 



Assuming the length of the pendulum vibrating seconds in 

 the latitude of London, viz. 51° 31' 08-4'' at 39-13929 inches, 

 which has been determined by Capt. Kater, the following table 

 is given by Capt. Sabine, as presenting its length at each of the 

 stations at which the clocks have been set up, deduced from the 

 observations detailed in this paper. 



Places of Observation. Latitude. ^^"X^"^*:^^" 



Inches. 



London 51° 31' 08-4'' N .... 39-13929 



Brassa 60 09 42-0 .... 39-16929 



Hare Island 70 26 1 7-0 .... 39*1984 



Melville Island. . . 74 47 12-4 .... 39-207 ' 



Capt. Sabine's paper concludes with deductions as to the 

 figure of the earth ; and he gives the following table as contain- 

 ing the diminution of gravity from the pole to the equator, and 

 the resulting elhpticity of the earth deduced from the preceding 

 observations ; and the method followed in obtaining these deduc- 

 tions, Capt. Sabine states to be the same as that described by 

 Capt. Kater in the Philosophical Transactions for 1819, p. 420, 

 421. 



Diminution of gravity. EUipticity. 



London and Brassa -0055066 .... -j-j-Tir 



London and Hare Island -0055082 ^^.^ 



Brassa and Hare Island -0055139 .... -jy^-.^ 



London and Melville Island . . . -0055258 -^^.^ 



11. Some Observatioiis and Experiments on the Papi/ri found in 

 the Rui}is of Ilerculaneum. By Sir Humphry Davy, Bart. PRS. 



This paper contains, first, a detail of the author's early experi- 

 ments in England on fragments of papyri ; secondly, a descrip- 

 tion of the rolls in the museum at Naples, and of some analytical 

 experiments made upon them ; thirdly, a detail of the various 

 chemical processes carried on in the museum at Naples on the 

 MSS. and of the reasons which induced Sir Humphry to renounce 

 his undertaking before it was completed ; and lastly, some 

 general observations on the MSS. of the ancients. 



As chlorine and iodine have no action upon pure carbo- 

 naceous matter, and a strong attraction for hydrogen, it was 

 conceived that they might be employed to destroy the matter 

 which occasions the adhesion of the leaves, without injuring 

 the carbon of which the ink is composed. 



A fragment of a brown MS. the layers of which were 

 strongly adherent, wasiramediately acted upon by being placed 



