126 



THE POPULAR SCIENCE MONTHLY. 



panies, we are told by Mr. James E. Whit- 

 ney, in the Railway 2vnes, that, of a lot of 

 axles furnished to the Mobile & Ohio 

 Railroad Company, but one-fourth were ca- 

 pable of meeting the required test, and the 

 other three-fourths were returned to the 

 manufacturer. Mr. Whitney also says that 

 the duty of making these tests belongs to 

 the railway companies themselves, which 

 leaves them no valid excuse for the employ- 

 ment of defective materials. 



Besides the use of poor iron, the resist- 

 ing power of the axle may also be lessened 

 by the method of manufacture. " The 

 ideal axle," says Mr. Whitney, " would have 

 its metal as dense as possible, and hence 

 would be shaped mainly by hammering. Its 

 fibres would run unbroken throughout its 

 length, and the tough outer skin, which in 

 wrought as in cast iron is much stronger 

 than that within, would be preserved in its 

 integrity." As now manufactured, a por- 

 tion of this is removed by turning, and the 

 axle proportionally weakened. The turn- 

 ing process is also carried to the formation 

 of sharp corners, which, as shown by Ran- 

 kin, eventually become the starting-points 

 of annular or circumferential grooves that 

 continue to deepen until the central por- 

 tion is too much diminished to bear the 

 shock of the unusual jar : " The ordinary 

 'tapping' will, in aggravated cases, enable 

 such a flaw to be detected, but no skill and 

 no care will guard against the slow but 

 sure approach of danger, because of the un- 

 necessary removal of a few annular chips 

 at the shoulder of the wheel-bearing, to 

 gratify the whim of the turner." 



But, however strong originally, car-axles 

 always deteriorate with use, the constant 

 succession of jars to which they are subject 

 gradually impairing the strength of the iron. 

 The character of this change is not well 

 understood, and the only effective method 

 now known, of guarding against the danger 

 arising from it, is to throw the axle aside 

 after it has been run a certain number of 

 miles. 



Bowlder-like Masses of Clay in Drift. 



Masses of stratified gravel, similar in shape 

 to the clay-bowlders mentioned in the March 

 number of this monthly as occurring in the 

 drift of Long Island, were found during the 



excavation of the Chicago Tunnel in the 

 drift under Lake Michigan. In the Ameri- 

 can Journal of Science for January, 1867, 

 Prof. E. Andrews thus describes tbem : 

 " They lay in all imaginable positions, some- 

 times with their strata set up at high an- 

 gles. They were from a few inches to a 

 few feet in diameter, and were embedded in 

 the solid, impervious clay nearly 80 feet 

 below the surface of the lake. The gravel 

 was water-worn, and often so clean that it 

 would scarcely soil a handkerchief. The 

 interstices commonly contained a few gal- 

 lons of water in the lower part, and some 

 air or gas in the upper. The gas was in 

 many instances inflammable. The pockets 

 scarcely leaked a drop when once emptied, 

 and the cavities looked exactly, in many 

 instances, like casts of rounded bowlders." 

 Prof. Andrews believes they were de- 

 posited as frozen masses which thawed after 

 they were embedded in the clay. This view 

 is corroborated by an experiment made two 

 years ago by Mr. E. Lewis, of Brooklyn. 

 During a period of cold weather he selected 

 an inlet of the sea through which the tidal 

 flow was rapid, and in which the water was 

 several degrees below freezing. The bot- 

 tom was frozen where the water was 10 feet 

 deep, but there was no ice on the surface. 

 A mass of frozen earth weighing about 50 

 pounds was sunk, by means of a cord, at the 

 deepest part of the inlet. Six days after- 

 ward this mass was unchanged, except that 

 its extreme surface was slightly soft and 

 moist. At the expiration of 30 days it was 

 again examined, and found to be somewhat 

 wasted. The temperature of the water 

 was then 3 above freezing. "If," says 

 Mr. Lewis, " this mass had been covered by 

 a quantity of sand or gravel, thrown down 

 upon it while frozen, it would have retained 

 its form ; and enormous masses of such ma- 

 terial are sometimes deposited suddenly 

 from floating ice and glaciers." 



Marked Case of Heredity in Mastiffs. 



Mr. Darwin communicates to Nature a let- 

 ter from Mr. Huggins on the hereditary 

 transmission, in a breed of mastiffs, of a 

 strong antipathy to butchers and butchers' 

 shops. Mr. Huggins owns a dog, " Kepler," 

 whose sire was a celebrated mastiff, " Turk." 

 When " Kepler " was six months old he fol- 



