820 Notes and Memoranda. 



The spots at which the shocks were felt might be enclosed in a polygon, of which 

 Paris, Auxerre, Tournus, Montbrison, Bordeaux, Nantes, and Kouen would form 

 the principal summits. The west-east shock was particularly felt in Dordogne, 

 Haute Vienne, and Charente on one hand, and Loire Inferieure and Orne on the 

 other. The south-north shock was chiefly felt in Indre, Indre et Loire, Loire-et- 

 Cher, Eure et-Loir, Seine-et-Oise, and Seine, being most violent in Indre et-Loir 

 and Soir-et-Cher. In Paris it was slight. At Perigueux the west-east shock 

 damaged many houses, and at Luche people at work were obliged to lean against 

 the walls to prevent their being thrown down. At St. Marc, near Orleans, two 

 persons were thrown down, the windows broken, and doors opened. Heavy noises 

 were heard at various places. 



Flint Coees feom the Indus. — The Geological Magazine for October has 

 a plate of remarkably neatly worked flint cores discovered by Lieut. Twemlow 

 three feet below the rock in the bed of the river, near Shikapoor, Upper Scinde, 

 and described by Mr. John Evans, who remarks that further details of the rock 

 must be obtained before their age can be determined. From their form alone he 

 would refer them to the neolithic rather than to the palaeolithic period of India. 

 The cores are composed of fawn-coloured flint, and flakes were struck from them 

 so as to have a regular polygonal pattern. 



The "Glass Bope" of the Hyolonema. — Dr. Gray has a paper in the 

 Annals of Natural History on the structure of the sponge Hyolonema Sieboldi, and 

 he considers that the researches of Professor Borboza du Bocage, who has found 

 the " glass ropes" with attached polyps off the coast of Portugal, show that the 

 long glass, or silica spicules do not, as Schulze and some other observers have 

 thought, belong to the sponge, but are formed by the polyps, as he affirmed long 

 ago. M. de Bocage did not find any object attached to these spicules, and as it 

 is plain they must have had some support, the evidence is inconclusive. We shall 

 shortly publish a paper on this subject, and therefore say no more now. 



Field Adjustment foe Object Finding. — A "Subscriber" writes: — 

 "When the position of a good specimen in a slide of Diatoniaceaj has been 

 marked, the recovery of the view is more difficult than would appear at first 

 sight, owing to the smallness of the marking, or indicating circle, and the size 

 and propinquity to the slide of the end of an object-glass such as Smith, Beck, 

 and Beck's one-eighth. If, however, the observer will incliue the body of the 

 microscope towards the horizontal position, and set the plane side of the mirror 

 to give an easy and convenient view of the end of the object-glass, the slide may 

 be put in exact position at once." 



The 90th Planet was discovered by Dr. Luther, of Bilk, near Dusseldorff, 

 on the 1st of October. It is of 11 mag. 2 Oct. E.A., Oh. 8m. 42s. 07 D— 2° 35' 

 42"'7. Daily movement in KA. 44s. in D — 4' "2. 



Poeosity of Caoutchouc. — M. Payen states in Comptes Rendus that a 

 microscopic examination of thin sheets of caoutchouc discloses minute holes or 

 pores, which are rounded, and communicate with each other. Contact with 

 liquids makes these pores more distinct. Vulcanized indian rubber exhibits nar- 

 rower cavities and concentric circles spreading from one pore to another, showing 

 successive zones of diminishing action of the sulphur. By exposure to water the 

 caoutchouc becomes whiter and opaque through absorbing the fluid. M. Payen 

 considers this porosity to be concerned in the dialytic action of indian rubber on 

 gases discovered by Professor Graham. 



Silveked Object Glasses foe Sun Viewing. — M. Le Verrier describes 

 in Comptes Rendus successful experiments made with an object-glass of 25 centi- 

 metres aperture. The silvering allowed excellent views of the sun to be made 

 with magnification up to 300. It is found that the blue tinge of light that has 

 passed through the silver film results from an elimination of the extreme red 

 rays ; nearly all the other rays passing through. 



Metallic Film Spectacles. — M. Melsens states in Comptes Rendus that 

 having suffered from an accident, by which his eyes were rendered exceedingly 

 averse to light, he found the greatest relief by employing spectacles containing 

 glasses covered with gold leaf, through which he could see the contour of bright 

 clouds. 



