96 Lt.-Col. Waterhouse exhibited photographs. [March, 



Other plates I prepared myself by dipping ordinary gelatine dry plates 

 into a bath of erythrosin with ammonia, also in a bath of erythrosin- silver 

 and ammonia prepared as recommended by Mallmann and Scolik. I had 

 tried Dr. Vogel's azalin dye but did not find it so good as the erythrosin. 

 Some of my plates were exceedingly sensitive, and pictures of the 

 illuminations taken on them shew a considerable amount of faint detail, 

 particularly one of the Town Hall which shows the windows and a good 

 many architectural details, with 3 minutes' exposure. Unfortunately 

 these plates shew a tendency to fog and will not bear intensifying suffi- 

 ciently to bring out these details in a print. 



The picture of the Financial Office, which was one of the best, though 

 it does not show architectural details, was taken on one of the French 

 Taillefer plates with 2J minutes' exposure. In this, as in some of the 

 others, the oil lamps have come out very well but not so strongly as the gas. 

 Some plates prepared with a mixture of cyanin blue and erythrosin, which 

 I had expected would be specially sensitive to the yellow light, were 

 found to be much less so than plates prepared with erythrosin alone. 



The photographs of the fireworks were taken mostly on the French 

 plates, but some of the plates I prepared myself gave very fair results. 

 The picture of the rockets, taken by my assistant Mr. Pope on one of the 

 French plates, is exceedingly curious; the very irregular paths taken by the 

 rockets being quite clearly shown though the exposure must have been 

 very short indeed. 



Some photographs taken in the Eden gardens, about 7 P. M., on 

 similar plates, may also be interesting. One of them, taken on a plate 

 stained with erythrosin- silver, with an exposure of only 70 seconds, 

 full aperture of an 8-in. focus rapid symmetrical lens, shows a great many 

 distant details that one would scarcely have expected. The possibility of 

 taking photographs at night of objects illuminated by the electric light 

 may be of importance in naval and military operations. 



As an illustration of the peculiar action of these orthochromatic 

 plates in photographing coloured objects I have brought two photographs 

 of a highly coloured chromo- lithograph. Both have been taken on 

 the Taillefer plates, but one with and the other without a yellow screen. 

 In the one case, although the plate shows a great deal more sensitiveness 

 to yellow than an ordinary dry plate does, the girl's yellow dress has 

 come out black, and the yellow spots of shading and tinting in various 

 parts of the picture, almost imperceptible on the original, have all repro- 

 duced black and alter the whole appearance of the picture. In the photo- 

 graph taken with the yellow screen the yellow dress is quite light, the 

 objectionable spots have disappeared, and the resulting photograph is a 

 very fair representation of the original chromo-lithograph. 



