I. HISTORICAL. 567 



Dr. Daiton's pupils (as is well known, he lived by teaching mathematics at 

 half-a-crown per lesson), in which the writer presents his " complements to 

 " Mr. Dalton, and is sorry that he will not be able to wait upon him to-day, 

 " as he is going to Liverpool with a few friends who are trying the railway 

 " for the first time. Mr. D. may fully expect him on Monday at the usual 

 time." 



No. 50 are bottles of tin, earthenware, and silver, some of them being 

 common penny pot ink bottles. Each has a thermometer tube cemented into 

 the neck of the bottle, and these tubes are provided with paper scales. These 

 were used by Dalton probably for experiments on radiant heat. 



No. 51 is a manometer tube used by Dalton; it consists of a tin vessel 

 attached on either side to leaden tubing, and having a thermometer-tube 

 closed at the upper end, and provided with a divided scale, fixed into the 

 upper portion of the tin vessel. 



No. 52, Dalton's Balance, made by Accuni, and capable of arrangement as 

 hydrostatic-balance with weights and counterpoises. 



2397. Frame containing proofs in John Dalton's hand- 

 writing of part of the " New System of Chemistry." Vol. II., 

 Part L, pages 347, 349, and 352. Prof. Roscoe, F.R.S. 



2397a. Receipt by John Dalton for instruction in 

 Chemistry. C. Law. 



2418. Press used by Dr. W. H. Wollaston, to compress 

 Platina, obtained in a fine state of division from precipitated 

 chloride. G. II. Wollaston. 



By means of this press the force obtained when the handle is at an angle 

 of 5 is very nearly 60 x by power, and at an angle of 1 very nearly 300 x by 

 power. 



2418a. Rhodium extracted from Platinum Ore by Dr* W. H. 

 Wollaston. Probably also contains Iridium and Ruthenium. 



G. H. Wollaston. 



241 8b. Platinum Crucible and Platinum Trough, used 

 by Dr. W. H. Wollaston. G. If. Wollaston. 



1738. Portion of the Battery used by Sir Humphry Davy 



in decomposing the alkalies. 



The Royal Institution of Great Britain. 

 Phil. Trans. 1808. 

 687b. Sir Humphry Davy's Laboratory Note Book. 



The Royal Institution of Great Britain. 



Davy's record of his decomposition of potash by the voltaic battery, 

 October 19, 1807. 



2405. Faraday's Apparatus for the Condensation and 

 Liquefaction of Gases. 



The Royal Institution of Great Britain. 



Apparatus used by Faraday for the condensation and liquefaction of gases, 

 consisting of condensing pump and connexions, conducting and other tubes, 

 gauges, sealed tubes for containing the liquefied gases, &c. &c. Phil. Trans. 

 1845. 



