396 Scientific Intelligence. 



(like a circular saw) exercises any drag upon the ether in its 

 immediate neighborhood. He uses two such discs of tough steel, 

 above a yard in diameter, rotating in parallel planes an inch 

 apart. Running the discs at 3000 revolutions per minute he can 

 discover no effect which can be attributed to any drag of the 

 ether. He has also replaced the discs by an oblate spheroid of 

 wrought iron with a deep channel or groove cut in it and wound 

 with wire ; but the rotation of this transversely magnetized mass 

 (weighing about a ton) does not set the ether in motion. — Nature, 

 Sept. 28, 1893. j. t. 



9. Chrono-photo graphic study of locomotion. — M. Maeey con- 

 tinues his work upon this subject. Reptiles are placed in a circu- 

 lar canal where they can run on indefinitely, the chrono-photo- 

 graphic apparatus being placed above the canal. Fishes are 

 made to swim in a similar canal which is illuminated from above, 

 so that they appear dark on a light ground. An eel and an 

 adder progress in the water in the same manner. A wave of 

 lateral inflexion runs incessantly from the head to the tail, and 

 the speed of background propagation of this wave is only slightly 

 superior to the velocity of translation of the animal itself. Iu 

 fishes, provided with fins, and in reptiles possessing feet, there re- 

 mains in general a more or less pronounced trace of the undu- 

 latory motion of reptation. — Comptes Rendus, Aug. 28; Nature, 

 Sept. 7, 1893. j. t. 



10. Electrical oscillations of very small toave-lengths. — Righi 

 continues the description of experiments he has conducted on this 

 subject (Nature, June 22, 1893). The oscillator consists of two 

 small metal spheres surrounded with oil and held by two rods of 

 ebonite. These spheres are placed between the discharging rods 

 of a large Holtz machine. With spheres 4 cm in diameter the 

 wave-length of the radiation obtained was 20 cm , while with 

 spheres of l-3 cm diameter the wave-iength was about 7 cm . The 

 resonator was of a novel form and was made from a rectangular 

 piece of silvered glass of such a size that its breadth was equal 

 to the length of the resonator required. The varnish was then 

 dissolved off the back of the silver and a line drawn through the 

 silver by means of a diamond, so as to divide the strip of silver 

 into two equal parts, and form a spark gap. By this means a 

 spark gap of one and two thousandths of a millimeter was ob- 

 tained. For radiations of 7*5 cm wave-length, the resonator was 

 made of a strip of silver 3*9 cm long and 0'2 cm in breadth. With 

 these small wave-lengths the sparks ceased to be visible when the 

 distance between the oscillator and the resonator was a meter, but 

 were visible at a distance of six meters from the oscillator when 

 a parabolic metallic reflector was placed behind the resonator. 

 The author has succeeded in producing interference by FresnePs 

 method of inclined mirrors. It was found that ebonite, paraffin 

 and rock salt are perfectly transparent. A plate, of mica l-7 mra 

 thick absorbs 10 per cent of the electric radiation, while a plate 

 of ordinary glass 8 mm thick absorbs 37 per cent and a piece of 



