102 



NATURE 



[Dec. 5, 1878 



seem to be producible by anything else in nature. Har- 

 monic instruments have been constructed to exhibit the 

 combination of two or more pairs of harmonic motions to 

 the eye ; for example, Blackburn' s pendulum, Lissajous' 

 forks, Wheatstone's kaleidophone, Yeates' vibrating 

 prisms, Donkin's and Tisley's harmonographs, and 

 Hopkins' electric diapason. Prof. Ayrton illustrated his 

 remarks by exhibiting these instruments in action. The 

 pendulum traced out the complex path of the combined 

 motions by a jet of falling sand, the forks or prisms by a 

 moving beam of light thrown on a screen, the kaleido- 

 phone by a bright bead, and the harmonograph by the 

 involutions of an aniline pen. With none of these and 

 such like instruments, however, is the production of mere 

 emotion the end in view ; and in some of them no change 

 can be made in the periods of the pairs of harmonic or 

 periodic motions combined without arresting the instru- 

 ment, a proceeding which in music would be analogous 

 to stopping the tune at the end of every chord. There is 

 no provision either for changing the amplitude or phase, 

 equivalent in music to an inability to render, at will, a 

 note forte or piano, or rather as it is not only the strength 

 of the entire note, but even the amplitude of the various 

 component harmonics that these instruments cannot 

 regulate, it would be as if in music there was the proba- 

 bility of a note marked in the score as piano for the flute 

 being rendered by a loud blast from a trumpet. A suc- 

 cessful instrument in the new kinematical art must at 

 least visibly render changes in period, amplitude, and 

 phase of the harmonic motions represented. Profs. Perry 

 and Ayrton had designed an instrument, which is now 

 in Japan, for effecting these required changes in a com- 

 bination of harmonic motions given to a moving body, 

 and which they claimed to be the first musical instru- 

 ment of the visual art in question. They had not given 

 it a name yet, because the nomenclature of the subject 

 was uninvented. Photographs and diagrams of this in- 

 strument were exhibited to the meeting. It consists of a 

 mechanical arrangement of sliders, pulleys, and cords, 

 whereby two motions, one along a vertical, and the other 

 along a horizontal line, and eac/t consisting of the sum of 

 a number of harmonic motions the period, amplitude, or 

 phase of any one of which can be varied at will, are com- 

 pounded in the resultant motion of a suspended pane of 

 glass. A black circle painted on the pane is intended to 

 represent the moving body as projected against a wall or 

 screen behind. The sliders controlling the motion of the 

 pane are actuated by a revolving barrel, the periphery 

 of which is carved according to mathematical principles, 

 so as to give the different harmonic motions to the shders 

 in one revolution. The motion is further regulated by 

 shifting the sliders either parallel to the axis or at right 

 angles to the radius of the revolving barrel ; and by the 

 angular velocity of the barrel. In this way the period, am- 

 plitude, and phase of the component motions of the glass 

 either in a vertical or horizontal direction, may be changed 

 at will, and almost immediately. Other kinds of periodic 

 motions may be compounded in a similar way. Prof. 

 Ayrton also suggested other forms of apparatus for this 

 purpose. Numberless combinations of graceful motions 

 producing emotional effects on the beholder can by its 

 means be given to a visible body. It is the intention of 

 the authors to construct an improved form of the appara- 

 tus, and to arrange for the blending of colour with the 

 moving body to heighten the emotional influence ; for 

 example, they purpose having changing mosaics of dif- 

 ferent hues, thrown upon the screen for a background to 

 the black spot. This can be done by means of an instru- 

 ment similar to the chromotrope with its revolving sheets 

 of parti-coloured glass. In conclusion Prof. Ayrton said 

 that there might yet be invented many different ways of 

 producing these spectacles, and there was no reason why 

 a whole city full of people should not enjoy these displays 

 projected upon the clouds overhead. 



THE SWEDISH NORTH-EAST PASSAGE 

 EXPEDITION 



FROM letters despatched from the mouth of the Lena 

 by Prof. Nordenskjold on August 27, which have just 

 been published in the Gothenburg Handels Tidning, we 

 learn that the Vega accompanied by the Lena left Dickson 

 Harbour, at the mouth of the Yenissej, on August 10, 

 the weather being fine. On the nth ice was seen, but it 

 consisted almost exclusively of bay ice which did not 

 obstruct navigation, which, however, was rendered diffi- 

 cult by a thick fog. The salinity of the water began 

 gradually to increase and its temperature to fall. Organic 

 life at the bottom grew richer at the same time, so that 

 Dr. Stuxberg on the night between August 13 and 14, 

 while the vessel lay anchored to a drift-ice floe, collected 

 with the swab a large number of beautiful pure marine 

 types ; for example, large specimens of the remarkable 

 crinoid, Alecto eschrichtii, numerous asterids {Asterias 

 linckii and panopld), pycnogonids, &c. The dredgings 

 near the land now too began to yield to Dr. Kjellman 

 several large marine algae. On the other hand the higher 

 plant and animal life on land was still so poor that the 

 coast here forms a complete desert in comparison with 

 the rocky shores of Spitzbergen or West Novaya Zemlya. 

 Auks, rotges, loons, and terns, which are met with on 

 Spitzbergen in thousands upon thousands, are here almost 

 completely absent. Gulls znd Lestris which there fill the air 

 with continual sound occur here only sparingly, each 

 with two species, and it appears as if they quarrelled less 

 with one another. Only the snow-bunting, six or seven 

 species of waders, and a few varieties of geese are found 

 on land in any great numbers. If we add a ptarmigan 

 or two, a snowy owl, and a species of falcon, we have 

 enumerated the whole bird fauna of the region, at least 

 so far as the Swedish expedition have been able to ascer- 

 tain it. Of warm-blooded animals in the neighbouring 

 sea, only two walruses and some seals, Phoca barbata and 

 hispida, were met with. There is probably great abun- 

 dance of fish. Cosmic dust was sought for on the ice 

 without success, but there was found upon it some yellow 

 specks which, on examination, were found to be a coarse- 

 grained sand, consisting exclusively of very beautifully- 

 formed crystals up to two millimetres in diameter. The 

 nature of these crystals was not ascertained, but it was 

 evident that they are not formed of any ordmary terres- 

 trial mineral, but possibly of some substance crystallised 

 out of the sea-water during the severe cold of winter. 



The Vega lay at anchor from August 14 to 18 in a 

 harbour named Actinia Harbour, from the number of 

 these animals brought up by the dredge from the sea- 

 bottom. This harbour is situated in a sound between 

 Taimyr Island and the mainland. The land was free of 

 snow, and covered with a greyish-green turf formed of a 

 close mixture of grasses, mosses, and lichens, forming 

 a reindeer pasture much superior to that of the valleys in 

 Spitzbergen which abound in reindeer. Only a few rein- 

 deer, however, were seen here, probably owing to the 

 presence of wolves. The number of phanerogamous 

 plants is exceedingly small ; the moss and especially the 

 lichen vegetation, on the other hand, abundant enough. 

 Actinia Harbour is an excellent position for a meteorolo- 

 gical station. The fog still continuing, the Vega and 

 the Le7ia sailed again on the i8th, and reached Cape 

 Chelyuskin on the igtb, anchoring in a little bay which 

 indents the low promontory, dividing it into two parts. 

 The western point was found to be situated in 77" 36' 

 n" N. L., and 103° 25A' E. from Greenwich, and the 

 eastern in 77° 41' N. L.," and 104° i' E. L. Inland the 

 mountains appeared to rise by degrees to a height of 

 1,000 feet. These mountains, as well as the plains, were 

 free of snow. Only here and there were to be seen large 

 white patches of snow in hollows on the mountain sides 

 or in some small depression on the plains. At the beach, 

 however, the ice-foot still remained at most places. 



