1809. JET. 31.] PROFESSOR DAVY. 361 



morning are on the excitation of radiant heat and elec- 

 tricity in different gases. For the experiments on 

 Friday, which will be on tellurium, there 

 are wanting very pure hydrogen ; two bot- 

 tles of new, very pure oxymuriatic gas ; two 

 new stopcocks cemented into retorts, with stop- 

 pers, either green or white ; some tubes of 



this bore f I or near it, closed at one 



O 



end and six inches long ; a spirit lamp made 

 from a phial of large bore and the tube larger 

 than that at present used. 



On September 14 he tried various experiments 

 on the excitation of electricity. The Laboratory Book 

 says, ' Present in these and the former experiments, 

 Mr. Cavendish, Dr. Herscbel, Mr. Herschel, Sir Charles 

 Blagden (not in the second set on electricity) ; Dr. 

 Wollaston, Mr. Warburton.' 



The repulsion of the machine was compared to the 

 repulsion in a partial vacuum, in hydrogen, in carbonic 

 acid, and in rarefied carbonic acid. The former experi- 

 ments the same day were on the rise of a thermometer 

 heated by a coil of platinum wire in different gases. 



On September 21 the Note-Book says : 



An Experiment to Decompose Muriatic Acid Gas. A 

 balloon having three openings, to one of which a stop- 

 cock was cemented, and in the other two were corks con- 

 taining wires, so adapted to each other that a contact might 

 be made. Pieces of well-burnt charcoal were fastened to 

 the ends of the wires. The apparatus, being air-tight, was 

 exhausted and filled with hydrogen ; another exhaustion 

 being made, the balloon was filled with oxymuriatic gas 

 from a gas-holder, with which it was connected by means 



