160 Notes and Memoranda. 



spots is 3, 41 : the depth of the spots is the shene of 0°*30 or of o, 57 the radius of 

 the earth. It is constant through the whole extent observed between +30° and 

 — 3CP of latitude. 3. Spots have a pendulum-like oscillation in latitude : the 

 period of these oscillations varies with the latitude, and appears to reach a 

 maximum of 150 to 160 days about the 14th degree. At 15 degrees from that 

 point it seems reduced about one-half. 4. Spots have an oscillating motion in 

 longitude corresponding with the same period, and the geometrical combination 

 of these movements operates as if the spot described in the direction of the 

 rotation an ellipse about its mean position, with its major axis directed from one 

 pole to the other. This singular rotation appears to have a direct connection 

 with the internal constitution of the sun." 



Me. Weay's Otect Glasses.— Mr. "Wray, of Clifton Villas, Highgate Hill, 

 recently brought before the Astronomical Society an account of his plans for 

 correcting the secondary spectra in object-glasses. He interposes " a thin meniscus 

 film of highly dispersive cement" between flint and crown glasses, and thus 

 obtains a perfect achromatic image. — Monthly Notices, January. 



Phantom Thumbs. — If any one looks steadily at a patch of moderately bright 

 light on a wall, and then gradually raises his hands, having the fingers 6hut, the 

 palms directed forwards, and the two thumbs touching at their tips, he will at 

 the moment the thumbs reach the level of the eye, see three thumbs instead of 

 two. The eyes should be directed steadily at the wall all the time, and not 

 attempt to look at the thumbs. Some persons see the illusion best when the 

 thumbs are within a few inches of the eye, and others do so when they are held 

 away at arm's length. Curious effects are produced by slowly separating the 

 thumbs as they reach the eye-level, and also by substituting fingers for thumbs. 



Bees' Eggs and theie Peodtjcts. — M. H. Landois, in Comptes Rendus, 

 recites experiments he made to te9t the truth of the proposition laid down by 

 Dzierzon and Von Siebold that working bees are hatched from eggs which the 

 queen fertilizes with sperms from her receptaculum seminis, while male bees issue 

 from eggs not so fecundated. By carefully removing eggs from cells destined for 

 the workers to those of the males, and vice versa, he altered the nature of their 

 inmates. Thus, he says, the difference of the food supplied to the inhabitants 

 of the two kinds of cell determines whether they will be males or workers. 



Plateau's Liquid. — For blowing the large persistent bubbles and exhibiting 

 experiments with films, M. Plateau states that pure oleate of soda dissolved with 

 gentle heat in distilled water, in about 40 of water, and then mixed with Price's 

 Glycerine, in the proportion of 3 parts of the oleate to 2*2 glycerine, gives the 

 best results. The mixture is fit for use one or two days after it has been made. 

 Bubbles blown with this liquid have lasted longer than twenty-four hours. The 

 fluids usually sold in London for these experiments are great rubbish. Some 

 respectable chemist should prepare the pure oleate. 



Boiling "Watee in Rotation. — M. Mousson wished to keep some water 

 boiling for several hours in a large glass globe with a flat bottom holding about 

 three litres, and heated with gas. The ebullition was weak, although facilitated 

 by copper turnings unequally distributed over the bottom of the vessel. Occa- 

 sional vapour bubbles preserved their dimensions uniform in their passage through 

 the liquid, showing the equal distribution of the heat. In order to make the 

 copper turnings assemble together above the flame he caused the vessel to rotate. 

 This immediately gave rise to an energetic whirlpool movement about the axis of 

 rotation, a sort of water column eight to ten millimetres in diameter revolving 

 rapidly, carrying up multitudes of copper particles. In the midst of this qolumn 

 was a constant disengagement of small bubbles, closely approximating, and making 

 a momentarv canal one millimetre in diameter. JS T o bubbles proceeded from other 

 parts of the' liquid. Kleine Physic, Mittheil. Archives des Sciences. 



■sens©* 



