locks 



sagacity 



SCIENTIFIC SIDE-LIGHTS 



594 



cold and covered with felt or other non- 

 conducting material; 'the surface of this 

 covering will have a certain temperature. 

 If now this vessel be covered with another 

 thickness of felt, the temperature of the 

 original surface will rise, and a certain gain 

 of its heat will be made by each additional 

 coating of non-conductive material. 



The only serious question is as to the 

 thickness of the rocks which have been laid 

 down on the sea-floors. Hardly any geol- 

 ogist will doubt that it is entirely within 

 bounds to assume that thickness much to 

 exceed twenty miles. SHALEB Aspects of 

 the Earth, p. 82. (S., 1900.) 



2936. ROENTGEN RAYS DEFY RE- 

 FLECTION OR REFRACTION A Force 

 Not To Be Diverted. An exceptional prop- 

 erty of these rays is that they cannot be 

 either refracted or reflected as can ordinary 

 light and heat. Hence it is only the shadow 

 that can be photographed. And another 

 curious result of this is that they can pass 

 through a powder as easily as through a 

 solid; whereas ordinary light cannot pass 

 through powdered glass or ice, owing to the 

 innumerable reflections and refractions 

 which soon absorb all the rays except those 

 reflected from a very thin surface layer. 

 Proportionate thicknesses of aluminum or 

 zinc, whether in the solid plate or in 

 powder, are equally transparent to these 

 singular rays. WALLACE The Wonderful 

 Century, ch. 5, p. 41. (D. M. & Co., 1899.) 



2937. ROMANCE OF ZOOLOGY 



Slaveholding Ants. Some species of ants 

 keep slaves for instance, the reddish ant 

 found in the meadows of Switzerland and 

 Alsace (Polyergus rufescens). It is not a 

 large, but a strong species, which has adopt- 

 ed the habit of sallying forth in troops from 

 time to time to make raids upon and plun- 

 der the nests of some weaker species, such 

 as the common Formica fusca. The object 

 is, however, not to destroy or devour the 

 ants they attack, but merely to carry off 

 the pupae to their own nest, where they 

 receive every care; the workers hatched 

 from them are then employed as servants, 

 or, to use the usual term, as slaves. These 

 slaves fulfil all the duties of the nest, which 

 would otherwise have fallen to the share 

 of the red workers; they feed the larvae, 

 build galleries and chambers, bring in food- 

 supplies, and even feed their lazy masters! 

 This is no fable, as was once thought, but 

 an ascertained fact, proved to be such early 

 in this century by Huber of Geneva, a cele- 

 brated observer of ants, and since fully con- 

 firmed by his pupil and successor, Auguste 

 Forel, as well as by Sir John Lubbock. I 

 have also convinced myself of the truth of 

 the assertion. WEISMANN Heredity, vol. ii, 

 ch. 9, p. 25. (01. P., 1897.) 



2938. ROOTS MAKING THEIR WAY 

 IN THE SOIL Tip of Radicle a Wonderful 

 Structure Final Purpose of Its Various 



Movements. We believe that there is no 

 structure in plants more wonderful, as far 

 as its functions are concerned, than the tip 

 of the radicle. If the tip be lightly pressed 

 or burnt or cut it transmits an influence 

 to the upper adjoining part, causing it to 

 bend away from the affected side; and, what 

 is more surprising, the tip can distinguish 

 between a slightly harder and softer object, 

 by which it is simultaneously pressed on 

 opposite sides. If, however, the radicle is 

 pressed by a similar object a little above 

 the tip, the pressed part does not transmit 

 any influence to the more distant parts, but 

 bends abruptly towards the object. If the 

 tip perceives the air to be moister on one 

 side than on the other, it likewise transmits 

 an influence to the upper adjoining part, 

 which bends towards the source of moisture. 

 When the tip is excited by light (tho in the 

 case of radicles this was ascertained in only 

 a single instance) the adjoining part bends 

 from the light, but when excited by gravita- 

 tion the same part bends towards the center 

 of gravity. In almost every case we can 

 clearly perceive the final purpose or advan- 

 tage of the several movements. Two, or 

 perhaps more, of the exciting causes often 

 act simultaneously on the tip, and one con- 

 quers the other, no doubt, in accordance with 

 its importance for the life of the plant. 

 The course pursued by the radicle in pene- 

 trating the ground must be determined by 

 the tip, hence it has acquired such diverse 

 kinds of sensitiveness. It is hardly an ex- 

 aggeration to say that the tip of the radicle 

 thus endowed, and having the power of di- 

 recting the movements of the adjoining 

 parts, acts like the brain of one of the lower 

 animals, the brain being seated within the 

 anterior end of the body, receiving impres- 

 sions from the sense-organs, and directing 

 the several movements. DARWIN Power of 

 Movement in Plants, ch. 12, p. 576. (A., 

 1900.) 



2939. ROYALTY AMONG BEES > The 



Queen Feared, yet Restrained. The victori- 

 ous queen riow presented a very singular 

 spectacle. She approached a royal cell and 

 took this moment for uttering the sound 

 and assuming that posture which strikes 

 the bees motionless. For some minutes it 

 seemed as if she would profit by the dread 

 exhibited by the workers on guard, open 

 the cell and destroy the young female. She 

 also prepared to mount the cell, but in doing 

 that she ceased to make the sound, and 

 quitted the attitude that paralyzes the bees. 

 Then, instantly, the guardians of the cell 

 took courage, and by means of tormenting 

 and biting the queen, caused her to retreat. 

 HUBER Nouvelles Observations sur les 

 Abeilles, p. 117. (Translated for Scientific 

 Side-Lights.} 



2940. SACRIFICE OF GEM TO SCI- 

 ENCE Burning of a Diamond in Oxygen. 

 Faraday thus describes the burning of a dia- 

 mond in oxygen by the concentrated rays of 



