102 On a New Series of Chemical Reactions produced by Light. [Recess, 



velopment of the cloud was like that of an organism, from a more or 

 less formless mass at the commencement, to a structure of marvellous 

 complexity. I have seen nothing so astonishing as the effect obtained, 

 on the 28th of October, with hydriodic acid. The cloud extended for 

 about 18 inches along the tube, and gradually shifted its position from the 

 end nearest the lamp to the most distant end. The portion quitted by 

 the cloud proper was filled by an amorphous haze, the decomposition 

 which was progressing lower down being here apparently complete. A 

 spectral cone turned its apex towards the distant end of the tube, and 

 from its circular base filmy drapery seemed to fall. Placed on the base of 

 the cone was an exquisite vase, from the interior of which sprung another 

 vase of similar shape ; over the edges of these vases fell the faintest clouds, 

 resembling spectral sheets of liquid. From the centre of the upper vase a 

 straight cord of cloud passed for some distance along the axis of the experi- 

 mental tube, and at each side of this cord two involved and highly iridescent 

 vortices were generated. The frontal portion of the cloud, which the cord 

 penetrated, assumed in succession the forms of roses, tulips, and sunflowers. 

 It also passed through the appearance of a series of beautifully shaped 

 bottles placed one within the other. Once it presented the shape of a fish, 

 with eyes, gills, and feelers. The light was suspended for several minutes, 

 and the tube and its cloud permitted to remain undisturbed in darkness. 

 On re -igniting the lamp, the cloud was seen apparently motionless within 

 the tube ; much of its colour had gone, but its beauty of form was 

 unimpaired. Many of its parts were calculated to remind one of Gassiot's 

 discharges ; but in complexity and, indeed, in beauty, the discharges would 

 not bear comparison with these arrangements of cloud. A friend to whom 

 I showed the cloud likened it to one of those jelly-like marine organisms 

 which a film barely capable of reflecting the light renders visible. In- 

 deed no other comparison is so suitable ; and not only did the perfect 

 symmetry of the exterior suggest this idea, but the exquisite casing and 

 folding of film within film suggested the internal economy of a highly 

 complex organism. The twoness of the animal form was displayed through- 

 out, and no coil, disk, or speck existed on one side of the axis of the tube 

 that had not its exact counterpart at an equal distance on the other. I 

 looked in wonder at this extraordinary production for nearly two hours *. 



The precise conditions necessary to render the production of the effects 

 observed with hydrobromic, hydrochloric, and hydriodic acids a certainty 

 have not yet been determined. Air, moreover, is the only vehicle which 

 has been employed here. I hazard no opinion as to the chemical nature 

 of these reactions. The dry acids, moreover, I have not yet examined. 



* "It is as perfect as if turned in a lathe." " It would prove exceedingly valuable 

 to pattern-designers," were remarks made by my assistants as they watched the experi- 

 ment. Mr. Ladd, who is- intimately acquainted with the phenomena of the electric 

 discharge through rarefied media, remarked that no effect he had ever seen could compete 

 in point of beauty and complexity with the appearance here imperfectly described. I 

 mention this to indicate how the phenomena affected other eyes than mine. 



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