] to lloyal Society, 



of determining the longitude of any other point in that circle, from 

 its latitude. 



The third paper was entitled, " Hygrometrical Observations made 

 on board His Majesty's surveying vessel ./Etna." Communicated 

 by Captain Beaufort, R.N., F.R.S. 



These observations extend from the 27th of March to the 6th of 

 July, 1834, and were made daily at 8 o'clock a.m., at noon, and at 

 4 o'clock p.m. They comprise the height of the barometer, the dew- 

 point, degrees of dryness on the thermometrical, and of moisture on 

 the hygrometrical scales, the elasticity of the vapour, and the number 

 of grains of vapour in a cubic foot j with occasional remarks. A se- 

 cond series is also given, exhibiting the progress of solar radiation. 



The fourth was a " Meteorological Register, from the 1st of Janu- 

 ary to the 1st of November, 1834," by Mr. Edward Barnett. Com- 

 municated by Capt. Beaufort, R.N , F.R.S. 



These observations, made during a voyage across the Atlantic, 

 relate chiefly to the temperatures of the air and of the surface of 

 the sea. 



The fifth was a " Meteorological Register, kept on board His 

 Majesty's Ship Thunder, between the 1st of January and the 30th of 

 June, 1834," by R. Owen, Commander. Communicated by Cap- 

 tain Beaufort, R.N., F.R.S. 



These observations relate to the state of the weather, the direction 

 and force of the wind, and the heights of the thermometer, and of the 

 marine and oil barometers. 



May 14. — A paper was read, entitled, " An Account of the Water 

 of the Well Zem-zem, with a qualitative analysis of the same by 

 Professor Faraday" j in a letter from John Davidson, Esq., to the Se- 

 cretaries, and communicated by them. 



The author having, during his stay at Jedda, the port of Mecca, 

 succeeded in procuring about three quarts of the water from the well 

 of Zem-zem, to which the Mahomedans ascribe a sacred character 

 and extraordinary virtues j and wishing to preserve this water for the 

 purposes of analysis, had the can in which it was contained carefully 

 sealed j but, unfortunately, on its arrival in the London Docks, the 

 can, notwithstanding the directions written on it, was opened, and 

 the gas with which it was highly charged, and by which it held in solu- 

 tion a very large quantity of iron and other matters, was allowed to 

 escape. The precipitate thrown down, in consequence of the loss of 

 this gas, was found, by Professor Faraday, to consist of carbonate of 

 protoxide of iron in the enormous proportion of 1008 grains to the 

 imperial pint of water. The clear fluid was neutral, and contained 

 much muriate, and a little sulphate, but no carbonate j together with 

 a little lime, potash, and soda. There was also found an alkaline ni- 

 trate in considerable quantity ; this Mr. Faraday conjectures to have 

 been saltpetre, which had been added to the water by the priests. 



The reading of a paper was commenced, entitled, " Observations 

 on the Theory of Respiration." By William Stevens, M.D., D.C.L., 

 Fellow of the Royal College of Physicians of Copenhagen, and of 

 Surgeons of London. Communicated by W. T. Brandc, Esq., V.P.R.S. 



