1818.] Royal Society. 457 



consists of three parts. The author commences by an historical 

 view of the different experiments performed by Watt, Robison, 

 Dalton, Biot, and others, on the elasticity of the vapours of various 

 substances at different temperatures ; and after pointing out 

 some errors into which he conceived these philosophers had 

 fallen, he describes the method which he followed in his own. 

 experiments. His method was to confine the vapour under 

 examination in a portion of a barometric tube, to which was 

 applied the flat bulb of a thermometer ; it was sufficiently sensible 

 to mark the exact decree of temperature from zero to 200° above 

 the boiling point, where the vapour of water will support a column 

 of mercury of 36 inches ; the apparatus is so contrived, that the 

 mercuiial column itself is not heated. The author then gives an 

 account of the physical properties of the vapour of water, of 

 alcohol, ether, and spirit of turpentine, from below the freezing 

 point to above that of boiling water. 



The second part of Dr. Ure's paper relates to thermometrical 

 admeasurement ; he does not think that Mr. Dalton has substan- 

 tiated his objections against the common thermometric scale, as 

 he thinks the increasing rate of expansion in the mercury is 

 exactly balanced by the circumstance of part of the mercury 

 rising out of the ball, the part to which the heat is always 

 applied, into the stem. In the third section the author attempts 

 to discover by experiment the temperature at which different 

 vapours acquire the same elastic force ; the results of his expe- 

 riments are placed in a table ; among others, the latent heat of 

 steam is stated to be 967°; that of alcohol, 442° ; of ether, 302°; 

 and of spirit of turpentine, 178°. 



May 7. — A paper, by Thomas Smith, Esq. was read, on the 

 peculiarity in the construction of the fangs of poisonous serpents. 



A paper, by Mr. Thos. Greatorex, was also read, on the height 

 of the mountains in the north of England, contained in a letter to 

 Dr. Young. His observations were principally directed to Skid- 

 daw, and by employing what appears to have been a very 

 accurate process of geometrical measurement, he found its 

 elevation to be 3,036 feet 3'5 inches. 



On the same evening a paper by B. Bevan, Esq. was read, 

 consisting of the results of a registering rain-gauge, kept at 

 Leighton, in Bedfordshire, in 1817. We are informed that there 

 were 614 hours of actual rain, that the average rate at which 

 the rain fell was "68 of an inch in a day ; the heaviest rain was 

 on June 27, which was at the rate of nine inches per day. 



May2\. — A paper, by John Pond, Esq. was read on the 

 different methods of constructing a catalogue of the fixed stars. 



A paper, by Lieut.-Col. Lambton, was also read, consisting of 

 an abstract of the results deduced from the measurement of aa 

 arc on the meridian, extending from 8° 10' to 1<S° N. latitude, 

 and in 78° E. longitude, running through Tinnevelly and Ben- 

 galore. 



