FRAGMENTS OF SCIENCE. 



863 



MINOR PARAGRAPHS. 



WHILE illustrating glacier movements to 

 the British Association, Prof. W. J. Sellers 

 said that pitch and glacier ice strikingly re- 

 semble each other in behaving as solids or 

 liquids, according to circumstances. On the 

 sudden application of force they are very 

 brittle, but behave as fluids when subjected 

 to gradual pull and pressure. Hence it is 

 possible to employ pitch in the construction 

 of working models of glaciers, in order to 

 get an insight into those internal movements 

 of real glaciers which are beyond the reach 

 of actual observation. The study of glacial 

 deposits has shown that many erratic bowl- 

 ders are transported during the Glacial period 

 from lower to higher levels hundreds of feet 

 and left stranded on the rocky flanks of 

 mountains. This standing difficulty in the 

 way of physical theories of glacial move- 

 ment has been explained by the study of 

 pitch models, by means of which it is found 

 that the lower layers of material, in ap- 

 proaching an obstacle, are carried up in an 

 ascending current. The inference, which is 

 confirmed by natural facts, is that similar 

 movements would certainly take place in ac- 

 tual glaciers. Further, a glacier sometimes 

 overrides its terminal without disturbing it, 

 and in an experiment performed by the author 

 this was exemplified, for pitch flowed for 

 several months over a ridge of loose material 

 without carrying a particle of it away. 



BELIEVING that the longest-tongued bees 

 are the most profitable they being able to 

 extract honey from the greatest depths within 

 the flowers yielding it MM. Charton and 

 Legros have devised methods for measuring 

 bees' tongues. M. Charton's apparatus con- 

 sists of a box covered with metallic netting, 

 and having the bottom slightly inclined. On 

 this bottom is spread a sweetened liquid which 

 the bees can reach only by passing their 

 tongues through the meshes of the netting. 

 The hive whose bees can suck farthest down 

 the inclined bottom is preserved as a stock 

 for reproduction. M. Legros uses a receiver 

 closed by a sheet of perforated tin plate, from 

 which the sweetened liquid is fixed at care- 

 fully adjusted distances. M. Legros finds 

 that the tongues of common unselected bees 

 are 6 '5 millimetres long, while the black 



French bees can extract sirup at a maximum 

 distance of 9'2 millimetres. The tongues of 

 the best American bees reach to 8'73 milli- 

 metres. 



THE domestic weeds of ancient civiliza- 

 tion, the roadside weeds and the cornfield 

 weeds, says W. B. Hemsley, in a recent issue 

 of Knowledge, have accompanied man in his 

 most distant wanderings, and in many in- 

 stances have developed increased vigor, and 

 a power of colonization unsurpassed by man 

 himself. In some instances the reproduction 

 and spread of these weeds are so rapid as to 

 become a great scourge to agriculture, over- 

 running and destroying crops almost as ef- 

 fectually as swarms of locusts, and laws have 

 been framed making it compulsory on farm- 

 ers to keep their land free of these prolific 

 strangers. During the last three or four 

 years the so-called Russian thistle (Salsola 

 kali, var. tragus) has been occupying the seri- 

 ous attention of the farmers of the Eastern 

 and Central States of North America. Thou- 

 sands of square miles are infested, and the 

 loss resulting therefrom in 1892 was esti- 

 mated to exceed two million dollars. 



PROP. JOHN MILN'S report of eight thou- 

 sand three hundred and thirty-one earth- 

 quake shocks recorded in Japan, in which 

 the position of the origin of each shock and 

 the extent of country disturbed by it are de- 

 scribed, deals further with the propagation 

 of earthquake disturbances on the surface of 

 the earth, and possibly through it. Elastic 

 gravitational waves travel in Japan, or thence 

 to Europe, as surface waves at a rate of 

 three thousand metres per second, increasing 

 in period as they proceed; these are the 

 earthquake disturbances proper. Preceding 

 them in Japan are minute vibrations, and 

 these apparently travel to Europe at a rate 

 of from about eight thousand to ten thousand 

 metres per second. It is suggested that they 

 may travel, not along the surface, but through 

 the mass of the earth, by some path, straight 

 or curved; and that with a speed greater 

 than would be expected if the globe were of 

 glass or steel. Dr. Rebeur Paschnitz is of 

 the opinion that if such be the case they 

 may throw light on the internal structure of 

 the globe. 



