574' 



THE POPULAR SCIENCE MONTHLY. 



that do best at high altitudes are those of 

 simple phthisis, in patients who are free from 

 cardiac, renal, or rheumatic complications, 

 and who exhibit a torpid reaction to the 

 disease. 



Increasing the Tractive Power of Lo- 

 COmotiveSt — Patents were granted in March 

 to Elias E. Rlcs and Albert H. Henderson 

 for methods and apparatus for increasing 

 the tractive power of locomotives and other 

 self-propelled rail vehicles. This is accom- 

 plished by increasing, by means of electricity, 

 the frictional adhesion between the driving- 

 wheels and the rails. The apparatus con- 

 sists of a dynamo-electric machine on the 

 locomotive, from which a current of elec- 

 tricity passes through a converter, and thence 

 through the driving-wheels in succession and 

 that portion of the rails between them. 

 Further, the current, which is of great vol- 

 ume and small motive force, is said to cause 

 enough heat at the point of contact to va- 

 porize at once any moisture on the rails, 

 thus overcoming the slipperiness caused by 

 snow and sleet. The inventors claim that, 

 by their plan, the tractive power can be 

 nearly doubled without increasing the weight 

 of the locomotive, that a 40-per-cent grade 

 can be more easily surmounted than a 7-per- 

 cent one under the old system, that trains 

 can be stopped and started much more 

 quickly than at present, and that the fric- 

 tion obtained is cheaper than sanding, with- 

 out its consequent wear. 



An Exhibition of Insects. — An exhibi- 

 tion of useful and injurious insects was held 

 in Paris a short time ago, at which five hun- 

 dred entries of objects were made. Great 

 pains were taken to awaken interest in it. 

 Prizes were offered to school-children for 

 the best compositions on their visits to it. 

 Conferences were held in the rooms on ques- 

 tions relating to the study of insects. Med- 

 als were offered to rural teachers who sent 

 collections gathered by themselves or their 

 pupils. Booksellers offered books to those 

 who sent the best collections and the best 

 papers on entomology. Anatomical prepa- 

 rations were shown by Dr. Ozouf represent- 

 ing the oi^ganization of the silk-worm in its 

 several states and of May-bugs ; silks from 

 Tonkin and Senegal ; oak silk-worms raised 



in the open air which furnish a silk identical 

 with the Chinese pongee ; living ant-hills 

 collected by M. Morel, a journeyman painter; 

 ant-lions which had excavated their dens in 

 the sand as if they had been in the woods ; 

 batrachians, lizards, adders, aquatic insects, 

 wasps building and repairing their nests, 

 bee-hives with windows through which the 

 bees could be seen at their work ; wasps' 

 nests from Senegal, remarkable for their 

 excessive hardness ; gall-nuts of various 

 kinds, and collections from several countries, 

 with illustrations of various features of in- 

 sect life and economy. 



Constrnction of Mythologies.— Closely 

 connected as mythology and folk-lore are 

 shown to have been, says Mr. J. A. Farrer, 

 it is difficult or impossible to say in any 

 given case whether the superstition is de- 

 rived from the myth or the myth from the 

 superstition. The usual method of inter- 

 pretation deduces superstition from mythol- 

 ogy, making the latter the primary starting- 

 point. But it is often quite as likely that 

 the custom was there first, and that the 

 myth made use of already existing customs ; 

 for instance, that the horse figured conspicu- 

 ously in legend because it had long been an 

 object of worship or superstition, is as like- 

 ly as that it became an object of worship or 

 superstition because it figured so conspicu- 

 ly in legend. The horse is thickly set in 

 folk-lore. In parts of Germany a horse's 

 head may still be seen over the doors of cat- 

 tle-stalls or about the houses — a custom 

 which survives among ourselves in the luck 

 attaching to a hoi'se's hoof. This, perhaps, 

 dates from the custom of our ancestors, 

 mentioned by Tacitus, of keeping white 

 horses in sacred groves at the public expense 

 and idle, and forecasting the future from 

 their neighings. A horse's neighing always 

 presaged victory to a warrior, as his silence 

 presaged defeat, and the French anticipated - 

 disaster at Agincourt from the fact of their 

 horses not neighing on the eve of the battle. 

 A horse's hoof under a child's pillow is sup- 

 posed to be a preventive from convulsions, 

 a horse's teeth are a safeguard against tooth- 

 ache, and houses at which they shy are 

 threatened with calamity. There is no rea- 

 son to look for any more abstruse explana- 

 tion for the part which animals, birds, fishes, 



