Royal Institution of Great Britain. 555 



illustrated by numerous drawings, models, and specimens, domestic, 

 mineralogical, and botanical. He reasoned upon the account of the 

 eruption of 79 A. D. given by Pliny, explaining some parts and 

 correcting others, by means of the superior knowledge now pos- 

 sessed of the history of the mountains, and the natural causes 

 brought into action by and connected with it. 



In the library, amongst many presents, models of useful ap- 

 paratus, &c. were some Kandyan productions, brought by Captain 

 Chapman from Ceylon j the most interesting of which were native 

 drawings relating to the revolt and punishment of Pilime Talarvie 

 in 1812, and the barbarous treatment of the wife and children of 

 Ehelypole. It was through the influence of these and similar pic- 

 torial appeals to the minds of the people, that the island at last 

 came into the possession of the British. 



March llth. Mr. Aitiger gave an account of the machinery 

 employed by Mr. Mordan in the manufacture of common pencils, 

 the leads for the ever-pointed pencils, and the Bramah's pens, the 

 latter machine being the invention of the late Mr. Bramah. Mr. 

 Mordan's own machinery, which is of the most beautiful, perfect, 

 and effective kind, was set up in the lecture-room in working order, 

 and all the operations of pencil and pen-making performed. Al- 

 though the beauty and power of the machine could be judged of by 

 its effects and its principles, and easily understood by the assistance 

 of verbal explanation, it would be impossible, by writing, to give an 

 intelligible account, unless it were also a long one, and accompanied 

 by numerous drawings. 



An improved mountain barometer was exhibited in the library by 

 Mr. Robinson of Devonshire Street, the column of which was di- 

 visible into two portions when not in use. The fragility of the tube 

 of a barometer, its inconvenient length, and the necessity of carrying 

 it in an inverted position, expose it to more frequent accidents than 

 perhaps any other instrument employed by the scientific traveller. 

 The objects of this contrivance are to reduce the length of the 

 barometer, when not in use, to one half of the usual length, and to 

 render the position in which it is conveyed indifferent, and thus 

 make it capable of safe and convenient transport. The one portion 

 of the instrument is a glass tube, of half the length of a barometer 

 tube in this tube the mercury is boiled: this tube is cemented into 

 a steel cistern, the tube projecting into the cistern nearly two-thirds 

 the length of the cistern ; this part forms, when in use, the upper 

 portion of the mercurial column. The other portion is a glass 

 syphon tube ; on the end of the longer leg of which is cemented 

 a steel screw, which screws into the cistern, forming an air-tight 

 joint : the cistern is not quite filled with mercury, the air oc- 

 cupying that space, being the agent employed to cause the 

 mercury to descend into the syphon. If now the syphon be 

 screwed to the cistern, and the instrument be put in ah erect 



