; 41' 



NA TURE 



\August 29, 1889 



have been broken in two, and rent to splinters, by lightning. 

 The first tree which he mentions, however, suggests very forcibly 

 that the " explosion " must have occurred at the core of the tree, 

 for long wedge- like splinters of the wood have been forced out- 

 wards, and are now projecting from the stem. The fact, also, 

 that the whole of the bark was in each case torn off, and pro- 

 jected in every direction round about the trees, can be accounted 

 for only by an impulse proceeding from the middle of the stem 

 southwards. One feature of the case which Mr. Griffith did not 

 mention is the twisting which seems to have occurred with the 

 second tree : the portion which is nearly broken off appeared to 

 have been twisted through about 90°, and the portion of the stem 

 which is left standing is also considerably twisted in the same 

 direction ; as to the stem, however, it is difficult to estimate how 

 much of the twisting may be due to the growth of the tree. 



That any part of the effects are due to wind, is, I think, quite 

 out of the question. It is indeed a curious sight to see two 

 sound oak-trees, some 6 or 8 feet in circumference at their base, 

 broken off, twisted, and torn to splinters, as if they had been so 

 much matchwood ; but one of the most remarkable features of 

 the case appears to me to be, that there are t'wo trees which have 

 been treated in almost exactly the same manner. If it were the 

 effect of one shock, that shock must have divided itself into 

 nearly equal portions, and must have struck two trees which are 

 some 30 yards apart, which do not stand in any isolated position, 

 and which are separated from each other by several other trees, 

 all of which remained untouched. On the other hand, it is quite 

 inconceivable that two shocks of such an exceptional character 

 should have occurred within a few yards of the same spot, and 

 should have produced identical effects of such an extraordinary 

 character. 



The case is one which certainly deserves investigation. 



Harpenden, August 18. Spencer Pickerikg. 



Some Lake Ontario Temperatures. 



There are, among the great lakes of the St. Lawrence, ex- 

 ceptional opportunities for observing the effect of heat and cold 

 upon large bodies of fresh water. The vast area and depth of 

 the lakes, the different latitudes in which they lie, and the ex- 

 tremes of heat and cold of the Canadian seasons, all combine to 

 render observations of interest. 



It thus far appears that, in their main expanse. Lake Superior 

 and the Georgian Bay (the eastern basin of Lake Huron) con- 

 stitute, in midsum.mer, great bodies of colder water — the former 

 registering at the surface as low as 39!° F. (Hind), and the 

 latter at 10 fathoms indicating 45° F. , and, at the bottom, even 

 lower than 39^° F. (Boulton). On the other hand, the lower 

 lakes, including Ontario, are shallower than Superior, lie in 

 warmer latitudes, have some affluent streams from even farther 

 south, and may be said to have perceptible, though light, cur- 

 rents through them. The temperatures of their waters are thus 

 very different from those of Lake Superior and the Georgian 

 Bay. Thus, on May 6 of this year, at 4.15 p.m., Commander 

 Boulton, R.N., found the surface of the water off Griffiths 

 Island, in the Georgian Bay, 35° F., and the bottom, at 60 

 fathoms, 35^° F. ; whilst on May 23, at 11 a.m., near the outlet 

 of Lake Ontario — my first soundings there — I found the air (the 

 day being calm and cloudy) 55° F., the surface-water 52^° F., 

 and the bottom at 13 fathoms 50^° F,, and this was after a cool 

 and exceptionally windy spring. 



Some general results, which seem warranted by very numerous 

 thermometer-readings near Kingston, may be of interest. The 

 north-east end of Lake Ontario here does not usually exceed 

 20 fathoms in depth, but through it flow into the St. Lawrence 

 all the waters of the great lakes. 



Areas of Water of Different Teniperattires. — At the surface 

 the water is not uniform m temperature, even at points relatively 

 near each other, and which appear to have the same conditions 

 — the variatrons being generally from 1° to 3°. At different 

 depths down to the bottom there are equally marked variations. 

 In the tributary streams similar results appear. In a shallow 

 creek fully exposed for an eighth of a mile to the sun's rays, and 

 slowly flowing over a succession of limestone ledges, the mer- 

 cury, in \\ inch of water on a warm June afternoon, could be 

 seen rising and falling between 81° and 83° F. Here there were 

 exceptional causes, but in the line of outflow from the lake to 

 the St. Lawrence the fluctuations are to be ascribed rather to 

 the great evaporation at the surface, and the cooler waters be- 

 neath ascending to supply the place of the evaporated water. 



As the evaporation would be irregular, varying with the passing 

 clouds, and the gusts of wind, the ascending currents would also 

 be irregular. These ascending waters would give rise to an 

 inflow at the bottom from the deeper and cooler parts of the 

 lake to take their place, and both these currents would be affected 

 by the general light onward flow of the lake waters towards the 

 entrance of the St. Lawrence. 



Gradttal Absorption of Heat. — The general rise in the tem- 

 perature of the Lake Ontario waters as the summer advances is 

 at first i^low compared with the general rise in the temperature 

 of the air, but as midsummer is reached, the rise is more rapid 

 both at the surface and at the bottom. A comparison with 

 temperatures from Lake Erie will, eventually, better explain 

 this. The circumstance, however, has its bearing on the well- 

 known modifying effect of great bodies of water on the climate 

 of the immediately surrounding land. In illustration of it, on June 

 14, at noon, when the air indicated 79|° F., the surface water 

 in the main channel — 2 miles from Kingston — was still as low 

 as 574° F., or only 5° higher than on May 23. On July 5, the 

 readings in the same place had increased to 693° F., with the 

 air at 79° F., and on July 10 to 74!° F., with the air at 92!° F., 

 the thermometer always being in the sun. The most marked 

 change was between June 25 and July 5, when the advance 

 registered was 9°. The bottom temperatures indicate somewhat 

 similar results. On May 23 at 13 fathoms the deep sea ther- 

 mometer registered 50^° F. ; on June 14 at 12 fathoms, 52° F. ; 

 on July 10 at 17 fathoms, 53° F. ; and on July 25 at 12 fathoms, 

 67° F. 



The absorption and retention of the sun's heat is, however, 

 most noticeable in the small streams and quiet pools. There we 

 find well illustrated the general proposition that in high tempera- 

 lures the surface of comparatively Stillwater, where unaffected by 

 deep under currents, absorbs and retains the heat of the pun to a 

 much greater degree than the immediately overlying air. A 

 marked example of this was observed in the shallow lightly flow- 

 ing stream already referred to, where on June 14 at 3 15 p.m. 

 the air at 3 feet above the water indicated a slight breeze 73° F., 

 and at the surface 76°, whilst the water at i\ inch registered 

 83° F., at 4 inches varied between 79^° and 82^°, and at 7 

 inches on the bottom fell to 724° F. The records of other 

 creeks did not indicate such extremes, but showed that each 

 stream in its current, bottom, and surroundings, may have cir- 

 cumstances which vary the temperature. In very shallow, still 

 pools, exposed freely to the sun and breeze, the difference be- 

 tween the air and water surface temperatures is even more 

 marked, the water on sunny afternoons in Jvme and July showing 

 about 11° higher range. In such shallow, still pools, however, 

 the water, though indicating some variation, is tolerably uniform 

 in temperature, even to the bottom. 



Effect of Channel Currents. — Near Rockport, among the 

 Thousand Islands, there is a broad and deep channel where the 

 current down the river runs at about 2 miles an hgur. Here at 

 37 fathoms, in different localities, the deep sea thermometer 

 gave the same readings as the surface thermometer, showing that 

 the water was completely churned up. 



Another illustration was in the Gananoqui River immediately 

 below the falls. The temperature at the bottom here on June 

 10 was 62|° F. ; a quarter of a mile down stream at the outlet to 

 the St. Lawrence, it was 61^° F. ; in the St. Lawrence, 150 

 yards off the outlet, 57° F. : and 200 yards further up the St. 

 Lawrence, 54!° F. ; the surface water at each of these points 

 varying only between 62 i° and 63° F. These records show how 

 the deeper and colder waters of the St. Lawrence gradually 

 asserted themselves on coming into contact with the Gananoqui 

 River waters. A. T. Drummond. 



The Yahgan. 



The tribe in Tierra del Fuego described by the Rev. C. 

 Aspinall are called the Yahgan (Jahgan being a German form and 

 not the English). The missionaries have translated the Gospels 

 into Yahgan with some interpolations of special English terms. 

 There are two or three other distinct languages for the scanty 

 population. It can be seen that the Yahgan is a language of Old 

 World roots, and words can be recognized that philologists de- 

 termine to be typical Aryan roots. The variety of languages is 

 a fact noticeable among small exogamous communities, and it is 

 a matter of interest to find such variety at the extremity of the 

 New World. H. C. 



