84 



KNOWLEDGE & SCIENTIFIC NEWS. 



May, 1904. 



the buds, which hang down round the stem, only open in 

 sunli,t,'ht at a temperature of not less than ahont 60° F. 

 26° C., the flowers shut up every night at varyin,t,' times 

 according to their age, opening again each morning for 

 several days, and each day the flower alters in appearance. 

 This can be seen in the drawing — the buds are hanging 

 round the stem — one flower is just opening; there are 

 two older flowers and several in an upright position 

 which have closed, and are about to form fruits. 

 Then the stamens are sensitive, and when touched move 

 away from the stigma. The way the flowers are arranged 

 on the stem is also interesting ; the buds hang down at 

 flrst, then move upwards during the night, and then bend 

 again into the vertical position before openmg as in fig. i 

 bud. There is a little joint or pulvinus on each flower stalk 

 where the bend takes place ; when the fruit is ripe a layer 

 of cork is formed at this joint and there the fruit is de- 



differs in size. It is capable of taking 350 photographs. 

 When ready for use, the disc is put into the machine, 

 which is light proof, and by means of a handle at the 

 side can be rotated, so that every part of the plate 

 is exposed before the small oblong opening in front 

 of the lens and the photographs appear in a spiral 

 on the disc. In ordinary kineniatograph work, the 

 handle is rotated at a uniform speed and a series of snap- 

 shots are produced, but for the work now required, it is 

 necessary to take time exposures, as photographs must be 

 taken at all times of the day and in all weathers ; a large 

 number of photographs are only wanted when rapid 

 movements, such as that made by the stamens when 

 touched or when a bud is opening, are taking place. 



For miny parts of the day a photograph taken once 

 every quarter of an hour is sufficient. 



The practical difficulties in this kind of photography 



Weather Plant lAbms prccatonus 



Fig-. 22. 



Fig. 23. 



Fig. 24. 



Fig. 22. — Photograpli. Position of leaves at 

 2.18 p.m.. on Marcii 31, 1P04. 



Fig. 23. — Pliotograpli. Position of leaves at 

 5.15 a.m., the whofe rachis is 

 moving up, tiioiigti tlie leaves 

 are not yet open. 



Fig. 24. Photograph. Position of leaves at 

 10 a.m., April 1, 1904. 



Fig. 25.— Shows the night position. 



Fig. 25. 



tached. This plant seemed, therefore, a very suitable 

 one for experiment. I aimed at photographing the in- 

 florescence at intervals wliile young, so as not only to 

 show the opening of the flowers, their closing at night, 

 and the movements of the stamens, but also the develop- 

 ment of the inflorescence from bud to fruit. I hoped in 

 this way to show the progress of the plant during several 

 months in a few minutes on the screen. 



My first experiments with a film kinematograph, 

 though successful enough to encourage me to proceed, 

 had many defects ; the machine was not constructed for 

 this sort of work, and the maker was unable to help in 

 adapting it. The celluloid film would not stand the 

 constant damp of the greenhouse, and this was only one 

 of the many difficulties encountered with this machine. 

 My most successful experiments have been with the 

 Kammatograph, in whicii the photographs are taken on a 

 glass disc instead of a film. The disc, 12 inches in dia- 

 meter (half of one is shown in fig. 16) is suspended in a 

 metal ring; it is coated with a sensitive emulsion, just 

 like any ordinary photographic plate, from which it only 



are rather overwhelming at first, but I have now over- 

 come the principal ones, and think that anyone who 

 cares to try the experiment for himself will find it 

 fairly easy. The expense of each negative plate is 2s. 6d. 

 and the positive is also 2S. 6d., so that the total cost of 

 each completed kinematograph picture is 5s., plus the ex- 

 pense of developing. If this is done professionally, each 

 plate costs is. to develop, thus bringing the cost up to 

 7s. The developing and printing are extremely simple 

 compared with a film negative, as all the 350 photographs 

 are developed and printed at the same time and in the 

 same way as an ordinary plate ; this seems to me a great 

 practical advantage. 



Two principal points must be considered : — 

 I. — The apparatus must be quite rigid, as the slightest 

 movement would spoil the whole result. Mr. Kamm has 

 now devised a very satisfactory stand for this purpose. 



2. — Each photograph must be exposed uniformly, and, 

 as they have to be taken at all times of day and night, 

 this at first was one of the greatest difficulties. By the 

 use of Wynne's actinometer, this difficu'ty was completely 



