The Montgolfer Balloon 131 



had fallen 2 and the barometer risen 0-08 inch. The 

 latter maintained this rise, while the tornado passed over, 

 but afterwards, by 5.45 p.m., it had fallen by the same 

 amount. The thermometer continued to fall during the 

 passage. Mr. Chappelsmith, who gives the account, con- 

 siders the phenomena to be consistent with the rotatory 

 theory, but indicative of an ascending column of air in the 

 axis of the tornado, with an influx of air towards it from 

 the sides. 



At the 79th meeting (Nov. 22nd) Colonel Sykes stated 

 that gutta-percha 1 had been discovered in the Peninsula 

 of India. 



Mr. Grove gave an account of a visit to the family of 

 M. Seguin, the inventor of wire-bridges and tubular boilers, 

 who has a large estate in the Cote d'Or, and related how his 

 great-uncle Montgolfier had discovered the balloon which 

 bears his name. He had been airing his wife's gowns, 

 and observed them to become inflated and tending to rise 

 when filled with heated air. On her return she found her 

 husband sending up little paper balloons, and thus originating 

 his invention. He then referred to experiments of M. Seguin 

 on the conversion of motion into heat, which formed the 

 subject of a discussion. 



At the 85th meeting (May 22nd, 1856) Dr. Playfair 

 described an improved method of nature-printing, due to 

 a student at Marlborough House. The object is dabbed 

 with lithographic ink, transferred to the stone, and then 

 worked upon by acid. By this means the ' velvety ' texture 

 of the leaves is perfectly retained. The impression may also 

 be transferred to copper and etched in the usual manner. 



Colonel James explained how greatly photography had 

 expedited the production of maps at the Ordnance Survey* 

 By employing it, the 25-inch map was reduced to the 6-inch 

 scale with perfect accuracy. 



1 Dr. W. Montgomerie, of the Indian Medical Service, introduced it to- 

 England for practical purposes in 1843, the Malacca Peninsula and Malay 

 Archipelago being the chief source of this juice of one or more species of 

 Isonandra, and by 1860 the quantity imported exceeded 16,000 cwt... 

 but it is now much greater 



