Mar. 9, 1888.] 



SCIENTIFIC NEWS. 



219 



change of climate ? Or has the whole country been 

 suddenly upheaved and suddenly depressed ? Have 

 they been entombed by a single catastrophe or by a 

 series ? etc. The controversy has of late become mixed 

 up with theological controversy, and, as usual, this 

 element has rather magnified the confusion and dis- 

 cordance of hypothesis. 



Under these circumstances I perpetrate the presump- 

 tion of offering an original explanation which, so far as I 

 can learn, is also new. It is this. Siberia, as a glance 

 at a good map will show, is a vast plain intersected with 

 very long sluggish rivers, extending over a great range 

 of latitude. In the winter the northern regions of this 

 great area include the very coldest part of the known 

 world. In the summer these plains are luxuriant to an 

 extent scarcely credible to those who have not expe- 

 rienced the torrid contradictions of an arctic summer, 

 due to the continuance of sunshine all through the day 

 and all the night. The southern limits of these plains 

 are fully within the temperate zone. The Irtish and 



carcases would drift with the first winter ice to the places 

 where they are now found, i.e., on the banks of rivers 

 which have been undermined by floods. 



THE LATE ECLIPSE OF THE MOON. 



THE subjoined illustration, taken from La Nature, 

 shows the successive stages of this eclipse as 

 represented in an intermittent photograph. The moon's 

 apparent course is traced as a luminous band. The 

 lens of the camera was alternately opened for four 

 seconds, closed for five minutes, then again opened and 

 closed as before, the operation being repeated until the 

 disc of the moon was entirely covered, and no further 

 proofs were obtainable. The practicability of taking 

 photographic views by moonlight was shown in 

 Scientific News, vol. i., p. 106, First Series; and on 

 p. 162 of the same volume we gave a continuous 

 photograph of the satellite during a partial eclipse. 



Intermittent photograph of the Eclipse of the Moon. 



lenisei rivers flow from the latitude of Venice into the 

 Arctic Ocean. 



My theory is, in the presence of these data, very 

 simple, viz., that the mammoths of old behaved on land 

 as the swallows of to-day behave in the air. We know 

 that the elephant can run, can persevere in running, 

 provided the ground is favourable for such locomotion. 

 What, then, was there to prevent such an animal from 

 following the sun at the rate of, say, 100 miles per day, 

 or 10 deg. of latitude per week, and thereby following 

 the growth of the great supplies of food that so large a 

 beast must require. Following the banks of one of the 

 great Siberian rivers, the southern journey of 2,000 and 

 odd miles would be a mere holiday trip for such mon- 

 sters, and the return journej' down hill still easier. 



But such journeys must have exposed them to occa- 

 sional disasters. An early and sudden arrival of winter, 

 a blizzard, or a flood, would in the ordinary course some- 

 times overwhelm the hindmost and sweep their carcases 

 into the river. As all these rivers flow northward, these 



SHIP WAVES. 



T^ VERY one who has watched a boat or ship pro- 

 -L-' grossing through comparativelj' still water, or a 

 water-fowl forging its way across some quiet pond, must 

 have noticed the waves or ripples which are caused 

 thereby, and which stretch out in a long series far and 

 wide on each side in the wake of the moving body. As 

 may well be imagined, owing to the peculiar complexity 

 of the circumstances, the scientific investigation of the 

 configuration and pattern of these waves forms a most 

 difficult problem, requiring for its solution great power 

 of reasoning and high mathematical skill. That the 

 subject, however, can be made popularly attractive has 

 been lately shown in a lecture delivered bj' Sir William 

 Thomson at the recent meeting of the Institution of 

 Mechanical Engineers in Edinburgh. The learned 

 lecturer defined a wave as '' the progression through 

 matter of a state of motion. Look at a field of corn on a 

 windy day. You see that there is something travelling 



