454 Royal Society. 



de Mendoza Rios, Esq. ; George Earl of Morton ; John 

 Pond, Esq., astronomer roval j William Hyde Wollaston, 

 M. D. ; and Thomas Voung, M. D. 



Of the new Council :— George Earl of Aberdeen ; Taylor 

 Combe, Esq. ; Sir Thomas Frankland, Bart. ; Silvester 

 Lord Glenberviej Philip Earl of Hardwicke j Matthew 

 Raper, Esq. ; Samuel Rogers, Esq. ; Smithson Tennant, 

 Esq. ; Rev. William Tooke j and Roger Wilbraham, Esq. 



Officers. — The right hon.Sir Joseph Banks, Bart. K. B., 

 President j Samuel Lysons, Esq. Treasurer; William Hyde 

 Wollaston, M.D. and Taylor Combe, Esq. Secretaries. 



Dec, 10. The Society again assembled, the right hon. 

 Sir Joseph Banks, Bart. President, in the chair, when a 

 paper by Mr. Smithson on ulmin was read. Mr. S. was so 

 fortunate as to procure a specimen from the same gentle- 

 man at Palermo, who originally forwarded it to Klaproth, 

 and consequently operated on a substance perfectly similar 

 to that of its original discoverer. The author found that 

 the characters given to the substance called ulmin by Dr. 

 T.Thomson are very incorrect; and instead of its being 

 a resinous substance, he found that it chiefly consisted of 

 extractive matter united with potash. It was very slightly 

 soluble in alcohol. Mr. S. made some experiments on the 

 juice and branches of English elm, which he found some- 

 what diflferent from the substance sent him from Sicily. He 

 did not, however, pursue his experiments so far as to de- 

 termine the exact nature of the matter obtained from the na- 

 tive tree. 



Dec. 17. Dr. Wollaston, availing bimself of the facts 

 reduced to practice by Leslie, in freezing water bv means 

 of evaporation in vacuo, described ^n instrument with 

 which this process might be effected for amusement. Taking 

 a glass tube of any length, such as used for barometers, 

 making a bulb on each end of it four times its diameter, 

 nearly filling one of these bulbs with water, exhausting the 

 tube of air by boiling the v\ ater, and hermetically sealing 

 il like a thermomeler, and afterwards plunging the bulb into 

 a mixture of sal; and snow, ice would be immediately formed. 

 This might be repeated as often as wished, in a tube three 

 feet long, when the effects of extracting heat from the water 

 would be very distinct to the eve. 



The astronomer royal, Mr. Pond, laid tiefore the Society 

 a table of the latitudes of some stars near the north pole, 

 ascertained with great accuracy by means of the newly- 

 erected mural circle, made by Mr. Troughton, and whic^ 

 Ijlr. P. seems to consider as approaching perfection. 



Si* 



