646 



THE NATURE BOOK 



flashes following the same track ? \\'ould 

 not these, with intervals of time amounting 

 to. say. a tenth of a second between each 

 flash, appear to flicker ? Yes, certainly ; 

 but do such multiple flashes occur ? 



The astonishing fact which the moving 

 camera has re\'ealed to us is that single 

 flashes are the exception in Nature, and 

 multiple flashes the rule ! Further, it 

 seems that the faster the camera is moved 

 and the more sensitive the plate employed, 

 the greater is the number of component 

 tlischarges that can be photographed, 

 although they all appear to the eye as one 

 flash. To show the manifold discharges 

 whicli can be photographed in a flash 

 which appeared as a single flash the illus- 

 tration on page 645 is given. This most 

 interesting photograph was secured by 

 Mr. Alex. Larsen at Chicago, who mounted 

 his camera on a whirling table. The main 

 features to which attention should be 

 drawn are the parallelism of all the flashes, 

 showing that they all followed the same 

 track ; the different intensities between the 

 individual discharges ; and finally the 

 great number of flashes involved. 



After looking at such a photograph 

 one can quite understand that a hght- 

 ning flash can be seen to flicker if it is 

 made up of many individual discharges 



of different intensity, as the photograph 

 indicates. 



There are many other points of interest 

 which both the eye and the camera have 

 revealed that cannot be alluded to here. 

 It is hoped, nevertheless, that sufficient 

 has been stated to whet the appetite of 

 the reader, and that he or she, as the case 

 may be, will not in future look upon 

 thunderstorms with the awe which has 

 given rise to the saying : " When it 

 thunders, the thief becomes honest." 



When thunderstorms occur during the 

 day-time the cloud and colour effects are 

 the chief source of attraction, and the 

 advent of colour photography will soon 

 render it possible to record, in addition to 

 the forms, the weird colours which are 

 often seen on the approach of such storms. 

 During the night the observer can revel 

 in the dehghts of recording the many 

 and interesting peculiarities of the brilliant 

 flashes. A thunderstorm can thus be 

 rendered a source of enjoyment whenever 

 it occurs. Those fully prepared and armed 

 with cameras can record the wild doings, 

 as recommended in one of Tennyson's 

 earlier poems : 



" . . . . Then from a throne 

 IMoiinted in heaven will shoot into the dark 

 .'^rows of lightning. I will stand and mark." 



W. J. S. LOCKYER. 



HOW TO KNOW THE WILD ANIMALS 



By DOUGLAS ENGLISH, B.A., F.R.P.S. 

 Author of "Wee Tim'rous Beasties," " Beasties Courageous," etc. 



THE SQUIRREL 



With Photographs by the Author 



A GES ago, one may fancy, a certain 

 J~\ woolly Marmot waxed fat and 

 kicked. He developed, indeed, such 

 petulance and devilry that he must needs 

 climb a rock, and thence fling whistled 

 insults at his companions. His descend- 

 ants developed not only tempers but 

 tails, and in due course became the race 

 of Squirrels. 



It is a race which is almost cosmopolitan 

 in range (.Vustralia and Madagascar 

 alone are Squirrel-less), and which 

 attains its highest distinction, so far 

 as size and colour are concerned, in 

 the Tropics. 



Our own Red Squirrel, our " lytill 

 sqerell, full of besynese " — I am enter- 

 tained to find that the latter quality has 



