314 



KNOWLEDGE. 



August, 1913. 



name, the number of the product in its series should be 

 included (for knowing this and the rays given by the product, 

 the position of the element in the periodic table, and hence its 

 chemical properties, would be known), and the series to which 

 the product belongs should be the root of the name. It is 

 probable that most of the changes, which give off a or P rays, 

 have now been discovered, and in order to allow for rayless 

 changes where there is no change of mass of the atom but 

 only a difference in configuration the method used in organic 

 chemistry to describe different isomerides (ortho, meta, and 

 para, and so on) might be imitated. 



It is to be hoped that before long the radioactive substances 

 will be satisfactorily named. 



THE MERCURY VAPOUR LAMP.— The Cooper Hewitt 

 mercury vapour lamp has been so improved that the great 

 objection, viz., the peculiar colour of the light, can now be 

 overcome. The inventor has succeeded in this by placing a 

 celluloid film stained with rhodamine behind the mercury 

 vapour which is giving out light. The rhodamine fluoresces 

 with a red colour, that is to say, the rhodamine is so stimulated 

 by the violet radiations of the mercury vapour that it gives 

 out rays of its own, which are most intense in the red. The 

 resulting luminosity makes a fairly good imitation of daylight. 



Professor Wood has noticed that when such a stained 

 fluorescent film is backed by white paper or porcelain the 

 luminosity is much greater than when backed by a silvered 

 surface, the reason being that only part of the fluorescent 

 radiation emerges from the film : the rest is internally reflected 

 and does not get out, unless a scattering reflector, such as a 

 matt white surface, is placed behind. The effect is somewhat 

 striking, and a considerable loss of fluorescent radiation is 

 shown often to occur owing to internal reflection. 



The "neon" light, devised by M. Claude, which has the 

 similar advantage of the mercury vapour lamp in being very 

 economical of current, also has the disadvantage of giving rise 

 to a light deficient in certain colours ; the light is rich in red, 

 but deficient in green and violet. M. Claude has been able 

 to combine his lamp with the mercury vapour lamp and over- 

 comes this difficulty. The mercury vapour lamp works with a 

 low voltage current, while the neon light is worked by a 

 current of high voltage and frequency. All the same, 

 M. Claude has succeeded in his most recent type of lamp in 

 combining the two quite satisfactorily. 



ZOOLOGY. 



By Professor J. Arthur Thomson, M.A., LL.D. 



RESPIRATION IN THE WATER BOATMAN.— A care- 

 ful study of the process of respiration in this well-known insect 

 (Notonecta), which rows on the surface of the water, has con- 

 vinced Frank Brocher that in ordinary circumstances, at the 

 surface, only the seventh abdominal stigmata are used, both 

 for inspiration and expiration. When the water boatman has 

 finished taking in air, and is about to dive, it makes more 



energetic expirations, and expels by all its stigmata the excess 

 of air which it has in its tracheal system. This expelled air 

 spreads round the body, to which a portion remains adherent, 

 while another portion returns to the atmosphere or is 

 entangled in bubbles about the abdomen. 



THE CIGARETTE BEETLE.— Mr. Charles R. Jones 

 has made an important study of the cigarette beetle (Lasio- 

 derma serricorne) in the Philippine Islands. It has been 

 prominent for many years as a destroyer of stored vegetable 

 products, and is one of the worst pests of the tobacco 

 industry. All the principal tropical and subtropical tobacco- 

 producing districts abound with it. The eggs are laid in small 

 folds in the dried tobacco, e.g., within the open tip of the 

 cigar or cigarette, or under the overlapping edges of the 

 wrapper. The larva, which is less than a millimetre in 

 length to begin with, eats small cylindrical galleries in the 

 tobacco, especially in the higher-grade tobacco. There is a 

 little Clerid beetle which feeds ravenously, both in its larval 

 and adult stages, upon the larvae and pupae of the cigarette 

 beetles, and acts as a useful check. It has been shown by 

 careful experiments that the cigarette bettle can be absolutely 

 controlled, without affecting the tobacco, by fumigations of 

 carbon bisulphide and hydrocyanic gas, and by using high and 

 low temperatures. 



FUNCTIONAL TEETH IN UPPER JAW OF SPERM 

 WHALE. — It has been regarded as one of the characteristics 

 of the Physeteridae — -the sperm whale or Cachalot family — 

 that functional teeth are confined to the lower jaw. In the 

 sperm whale, indeed, it is well known that numerous rudi- 

 mentary teeth occur in the upper jaw ; but these have been 

 held to be relatively small, embedded in the gum so that they 

 do not reach the surface, and necessarily, therefore, altogether 

 functionless. It is recorded, however, by Messrs. James 

 Ritchie and A. J. H. Edwards that two out of seven 

 specimens examined at Bunaveneader in Harris bore visible 

 exposed teeth in the upper jaw. They lay in a row along 

 a well-defined groove running the length of the jaw on the 

 inner side of the depressions caused by the mandibular teeth. 

 There were about a score, each eleven centimetres long, all 

 but the tip embedded in the gum, far removed from the 

 maxillary bones. The worn and scratched surface afforded 

 proof of actual use. 



LARGEST AND STATELIEST OF BRITISH 

 COELENTERATA. — These words are applied by Professor 

 Herdman to the giant sea-pen, Funiculina quadrangttlaris, 

 which occurs abundantly in certain limited localities on the 

 west coast of Scotland. There appear to be " forests " of 

 them — flexible unbranched colonies fixed in the mud and 

 rising gracefully into the water. The finest specimen obtained 

 in 1912 was sixty-two inches in height, and several were about 

 five feet. Sir Wyville Thomson referred long ago to their 

 " pale lilac phosphorescence"; Professor Herdman notes their 

 "' pale translucent rosy tint." ■ 



SOLAR DISTURBANCES DURING JUNE, 1913 



By FRANK C. DENNETT. 



There is very little to record by way of disturbance on the 

 Sun during June, notwithstanding that the disc has been 

 telescopically examined every day. The falling off of activity 

 has been as marked as that at the beginning of 1912. 



On the 1st, 4th and 8th there were traces of tiny dark 

 spots, but these were not sufficiently evident to have their 

 positions measured. 



Even faculae have been comparatively few and far between. 

 On the 4th, minute faculae were visible within a few degrees 

 of both the South and North Poles. On the 14th a small 

 facula was situated Longitude 69° and Latitude 23° N., there- 

 fore approaching the North -Western limb. There was a pale 

 faculic patch on the 28th in Longitude 245°, Latitude 29° S., 

 and so nearing the South-Western limb. Other pale faculae 

 were seen North-East on the 4th, 5th, 7th and 8th; South- 



west on the 8th; South-East on the 7th and 8th ; and near the 

 centre of the disc on the 4th and 5th. 



Whilst looking at the projected image of the Sun upon the 

 focusing ground glass of the 4-inch photo - heliograph, 

 formerly in use at Greenwich Observatory, when only one 

 small spotlet was visible, a visitor was heard to remark that 

 he was unaware the Sun ever had so few spots as one. But 

 frequently of late the disc has presented a complete blank. 

 By the kindness of the Astronomer- Royal we are enabled to 

 reproduce a print from the original negative of the Sun taken 

 at the Cape of Good Hope on the morning of April 22nd, 1913, 

 when the disc was devoid of all disturbance except a very 

 small group of faculae near the N.E. limb (see Figure 343 

 and Figure 344 given for comparison). 



The observers were Messrs. J. McIIarg, A. A. Buss, E. E. 

 Peacock, J. C. Simpson and F. C. Dennett. 



