58 PHILOSOPHICAL TRANSACTIONS, [aNNO 17/6. 



London, at this time, comes out 72° 30', the different needles all agreeing 

 within 14', which is a difference considerably less than I should have expected. 

 It appears also, that the dipping needle, in the situation in whicli it is placed at 

 the Society's house, is not much affected by any iron work, as the dip shown by 

 it in the garden differs only 7' from that set down in the journal of the weather. 

 According to Norman, the inventor of the dip[)ing needle, the dip at London 

 in the year 1576 was7l" 50';* in 1676 it was 73° 4/', according to Mr. Bond ;-!- 

 Mr. Whiston in I720 made it 75° 10';+ Mr. Graham in 1723 made it between 

 73-L and 7i>°,^ his different trials varying so much ; and at present it appears to 

 be 72° 30'. I do not know how much Mr. Bond's determination is to be 

 depended on, as he does not say by what means he arrived at it ; but I believe 

 Mr. Whiston's is pretty accurate, for he observed the dip in many parts of the 

 kingdom, and the observations agree well together ; so that it is reasonable to 

 suppose, that his instrument was a good one, and that he observed in places 

 where the needle was not much influenced by iron work. The dip therefore 

 seems to have been considerably greater about the year 1720, than it was in 

 Norman's time, or is at present : it appears however to alter very slowly in com- 

 parison of the variation. 



XXIJ.^ The Method taken for Preserving the Health of the Crew of his Ma- 

 jesty's Ship the Resolution during her late Voyage round the JVorld. By Cap- 

 tain James Cook, F. R. S. p. 402. 



As many gentlemen have expressed some surprize at the uncommon good 

 state of health which the crew of the Resolution, under my command, expe- 

 rienced during her late voyage; I take the liberty to communicate the methods 

 that were taken to obtain that end. Much was owing to the extraordinary at- 

 tention given by the Admiralty, in causing such articles to be put on board, as 

 either by experience or conjecture were judged to tend most to preserve the 

 health of seamen. I shall not trespass on your time in mentioning all those 

 articles, but confine myself to such as were found the most useful. 



We had on board a large quantity of malt, of which was made sweet wort, 

 and given (not only to those men who had manifest symptoms of the scurvy, 

 but to such also as were, from circumstances, judged to be most liable to that 

 disorder) from 1 to 2 or 3 pints in the day to each man, or in such proportion as 

 the surgeon thought necessary ; which sometimes amounted to 3 quarts in the 



• New Attractive, c. 4. — Orig. + Ixmgitude found, p. 65. — Orig. 



X Longitude and Latitude found by dipping needle, p. 7, ^9, and 94. — Orig. 

 § Phil. Trans. No. 389, p. 332. — Orig. 

 1 For tliis paper, Capt. Cook was honoured with the gold medal, which is annuallj presented by 

 the R. s. 



