164 



Capt. Abney. On the Effect of the [Dec. 15 r 



Pier ate of fi-Lididine. 



When /3-lntidine is added to a strong boiling solution of picric acid, 

 most of the salt formed settles out as an oil, owing to its insolubility 

 and fusibility, but it becomes a solid crystalline mass on cooling. On 

 redissolving the solid in boiling water, and allowing the solution to 

 cool, the vessel becomes filled with brilliant yellow needles. They 

 were burnt with oxide of copper, with the necessary precautions, and 

 gave the following numbers : — 



Experiment. Mean. Calculation. 

 i " n , " , 



46-77 46-75 46-80 46-77 46-43 C 13 156 



4-11 4-16 3-94 4-07 3-57 H 1:3 12 



.... 16-67 N 4 56 



3333 07 112 



100-00 336 

 The formula is, therefore — 



C 6 H 2 (H. C 7 H 9 N)3(N0 3 ) . O . 



Action of Chlorine on fi-Lutidine in presence of Iodine. 



The chlorination of /3-lutidine was effected by Hugo Miiller's method ; 

 for this purpose iodine was added to the alkaloid, the mixture was 

 heated to 100°, and a current of chlorine was passed through until com- 

 plete saturation. The product was a dark reddish-brown fluid, which 

 was distilled. The portion boiling below 220° was washed^with a dilute 

 solution of hydrate of sodium, and then treated with hydrochloric 

 acid, a viscid green substance of peculiar odour remained undissolved. 

 On adding solution of platinic chloride to the filtered liquid, a 

 granular precipitate was obtained ; it was washed, dried, and the per- 

 centage of platinum determined : it amounted to 23'49 per cent. 

 The formula 2(C 7 H 6 Cl 3 N.HCl)PtCr 4 requires 2374. This result 

 shows that the product is a trichlorinated ^3-lutidine retaining the 

 basic properties of the original alkaloid. 



V. " On the Effect of the Spectrum on the Haloid Salts of 

 Silver, and on Mixtures of the same." By Captain Abney, 

 R.E., F.R.S. Communicated to the Royal Society at the 

 request of the Committee on Solar Physics. Received 

 December 6, 1881. 



There have been many investigations as to the sensitiveness to the 

 spectrum of the haloid salts of silver, from the very earliest days of 

 photography ; and when the results obtained by the different investi- 



Carbon. . . 

 Hydrogen 

 Nitrogen . 

 Oxygen . . 



