436 



The Earl of Rosse on the Radiation of 



[May 27, 



application of the irritant. When the circulation is about to be resumed, 

 the stagnating mass in the vessel appears to thaw as it were. The corpuscles 

 are not pushed onwards in mass as a coherent plug ; but the homogeneity 

 of appearance is suddenly lost by the resumption of their normal form by 

 the corpuscles and the reappearance of their differentiating outlines, which 

 were previously obscured by their blending with one another and with the 

 walls of the vessels. Before this takes place, the vessel very gradually 

 assumes a lighter tint, passing in some instances from a deep red to a pale 

 orange. This appears to be due to a washing away of extruded colouring- 

 matter. 



When this change from homogeneity to heterogeneity commences, 

 although sufficiently progressive in its character as it traverses the vessel, 

 it nevertheless takes place with considerable rapidity. It is evidently 

 brought about by the gradual permeation of new liquor sanguinis among the 

 corpuscles, and the contemporaneous abolition of their cohesive attraction 

 for each other in accordance with the principles previously established. 



II. " Researches on Turacine, an Animal Pigment containing Copper." 



By A. W. Church, M.A. Oxon., Professor of Chemistry in the 

 Royal Agricultural College, Cirencester. Communicated by Dr. 

 W. A. Miller, Treas. R.S. Received May 4, 1869. 

 (Abstract.) 



From four species of Touraco, or Plantain-eater, the author has ex- 

 tracted a remarkable red pigment. It occurs in about fifteen of the primary 

 and secondary pinion feathers of the birds in question, and may be ex- 

 tracted by a dilute alkaline solution, and reprecipitated without change 

 by an acid. It is distinguished from all other natural pigments yet iso- 

 lated, by the presence of 5*9 per cent, of copper, which cannot be removed 

 without the destruction of the colouring- matter itself. The author pro- 

 poses the name turacine for this pigment. The spectrum of turacine 

 shows two black absorption-bands, similar to those of scarlet cruorine ; 

 turacine, however, differs from cruorine in many particulars. It exhibits 

 great constancy of composition, even when derived from different genera 

 and species of Plantain-eater ; as, for example, the Musophaga violacea, 

 the Corythaix albo-cristata, and the C. porphyreolopha. 



III. "On the Radiation of Heat from the Moon." By the Earl 



of Rosse, F.R.S. Received May 27, 1869. 



The following experiments on Lunar Radiant Heat were undertaken 

 with the view of ascertaining whether with more powerful and more 

 suitable means than those previously employed by others, with little or 

 no success, it would be possible to detect and estimate the amount of heat 

 which reaches the earth's surface from the moon. 



