582 



Presents. 



[June 10, 



seems to appear in tlie De Meritens arc, but is much less fully deve- 

 loped. The spectrum we have figured does not by any means exhaust 

 the ultra-violet spectra of the flames we have observed, but it is as 

 much as we have been able at present to observe closely and to trace 

 to water as its cause. In writing of this and other spectra which we 

 have traced to be due to compounds, we abstain from speculating upon 

 the particular molecular condition or stage of combination or decom- 

 position, which may give rise to such spectra. The interest of finding 

 an ultra-violet spectrum of water in a flame at all seemed to justify 

 our laying before the Society so much as we have already determined. 

 It opens up questions as to the emissive power for radiation of short 

 wave-length of gaseous substances at the comparatively low tempera- 

 tures of flames, with regard to which we are accumulating facts, which 

 we propose to discuss in a future communication. It is obvious, how- 

 ever, that this opens up a very large and extensive field of inquiry 

 which will necessitate great precautions in the conduct of the experi- 

 ments ; for instance, we are not prepared to guarantee that oxides of 

 nitrogen from traces of air may not have something to do with some 

 parts of the spectrum here described. Such facts as we have placed 

 before the Society will completely modify the inferences which have 

 been drawn as to the assumed continuity of flame spectra even under 

 compression, and as to the character of the specific absorption of the 

 vapour of water. 



The Society adjourned over the Long Vacation to Thursday, 

 November 18 th. 



Presents, June 10, 1880. 



Transactions. 



Baltimore : — Johns Hopkins University. Circular No. 3. 4to. Balti- 

 more 1880. The University. 



Batavia : — Genootschap van Kunsten en Wetenschappen. Notulen, 

 Deel 17. Nos. 2-4. Register op de Notulen, 1867-78. 8vo. 

 Batavia 1879. Tijdschrift voor Indische Taal-, Land- en Vol- 

 kenkunde, Deel XXV, Aflevering 4-6 ; Deel XXVI, Aflevering 

 1. 8vo. Batavia 1879-80. The Society. 



Berlin : — K. Preussiche Akademie der Wissenschaften. Monatsbe- 

 richt, Sept., 1879, to Feb., 1880. 870. Berlin 1879-80. 



The Academy. 



Brussels : — Academie Royale de Medccine. Bulletin, 1879, Nos. 10, 

 11; 1880, Nos. 1-4. 8vo. Bruxelles 1879-80. Memoires 

 Couronnes. Tome V, Fasc. 4, 5. Svo. Bruxelles 1880. 



The Academy. 



