33 2 



NA TURE 



[Feb. 5, 1885 



intersected the field curve for the second time, and thence con- 

 tinued above it till midnight. The difference in the maxima of 

 the two curves was considerably greater than the difference in 

 their minima, that is to say, the wood exercised during the day 

 a more powerful cooling influence than it exerted a warming 

 influence during the night. The maximum of the forest curve, 

 besides, occurred from half an hour to an hour later than that 

 of the field curve. For the further study of the influence of 

 forests on temperature, the data of the maximum and minimum 

 thermometers were utilised. From these were calculated the 

 daily variations of temperature for the different months at the 

 different stations, and the yearly course of these variations for 

 each particular field and forest station was exhibited by a curve, 

 the absci s sfe of which were the months and their ordinates the 

 mean daily oscillations of temperature. From the curves of the 

 various stations, special curves for the open field, the fir, pine, 

 and beech forests were next deduced. The curve for the field 

 station showed that the daily variations in January and February 

 were within narrow limits and pretty similar, that in March the 

 curve rose, then mounted very rapidly in spring and up to its 

 summer maximum, whence in September it dropped very 

 rapidly, ahating, however, its rate of fall in October, and then 

 creeping down very slowly through November and December. 

 The curve for the fir forest was, in January and February, not 

 much different from the foregoing in the same months, 

 but the variations were smaller than in the case of the 

 field station. The curve next rose rather more steeply on 

 to the month of May, and after that proceeded more 

 slowly towards its summer maximum, from which it fell, at 

 first quickly and then slowly. All along, however, it l<ept 

 inferior to the curve of the field station, the interval between 

 the two being much greater in summer than in winter. In the 

 pine forest the curve marking the variations of temperature 

 showed a similar course, except that from January to April it 

 approached much nearer the curve of the field station than did 

 the curve of the fir forest, while in summer, on the other hand, 

 it kept at a greater distance from that of the field station, but 

 joined the fir-forest curve in autumn. Thus the curve of the 

 pine forest likewise all along kept below that of the field station. 

 The difference between them was less in winter, and in summer it 

 was almost just as great as the difference between the field curve 

 and the fir-forest curve. Altogether different, however, was the 

 curve of temperature and its variations in the beech forest. In 

 January and February it lay at but a very little interval below 

 that of the field station, came up almost quite level with it in 

 spring, or even shot just a very little beyond it, attained its 

 maximum for the year in May, whence it at first rather slowly, 

 but afterwards very rapidly, declined. In the beech forest, there- 

 fore, after it put on its full foliage in May, the variations of tem- 

 perature lowered considerably, showing a very wide difference 

 throughout the months of July and August from the variations 

 of temperature obtained for the same period in the open field. 

 The disfoliaged forest, on the other hand, showed hardly any 

 sign of having affected the variations of temperature. The 

 maxima, as also the minima, of temperatures were likewise 

 calculated by the month for the different stations, and from the 

 data thus obtained the annual curve was drawn. For the open 

 field the curves of the maximum and of the minimum temperatures 

 showed a pretty similar course, the maximum of both occurring 

 in summer, and the rise and fall of the curves being likewise 

 tolerably uniform. For the forest station the curves of the 

 maximum and of the minimum temperatures were different. 

 The maximum curve lay, on the whole, lower than the corre- 

 sponding curve of the open field. It moreover attained its 

 utmost height in May, resting there, with but slight changes, 

 throughout the summer. In autumn the curve sank, reaching, 

 in winter, quantities not essentially different from those of the 

 field curve. The curve of minimum temperatures, on the other 

 hand, in the case of the forest station, showed higher values than 

 obtained in the case of the free station. In the pine forest the 

 course of the minimum curve came nearer to that of the field 

 curve, and there, too, a maximum was found in summer. In 

 the beech forest, however, the curve attained its maximum as 

 early as May, keeping that level pretty nearly all through the 

 summer, but sinking more rapidly in autumn, and descending 

 lower than did the curve of the pine-forest station. As a result 

 of his investigation, Prof. Muttricn had arrived at certain definite 

 conclusions respecting the influence of the forest on temperature, 

 which maybe stated as follow : — (1) The forest exercised a positive 

 influence on the temperature of the air ; (2) the daily variations 

 of temperature were lessened by the forest, and in summer more 



than in winter ; (3) the influence of the leafy forest was in 

 summer greater than that of the pine forest, while in winter the 

 tempering influence of the pine forest preponderated over that of 

 the disfoliaged forest. An attempt to determining the influence 

 of the forest on the mean annual temperature led to no sure 

 results. 



Stockholm 



Royal Academy of Sciences, January 14. — Prof. Sven 



Loven gave an account of the work done last summer at the 

 zoological station of the Academy, and of the special reports 

 thereon by Dr. Carl Aurivillius on Ostracoda, M. Wiren on 

 Annelida, and M. Fristedt on sponges. — Prof. Loven also gave 

 the results of his studies on the species of echinoids described 

 by Linnseu=, the fundamental specimens of which, formerly in 

 the cabinet of Queen Lovisa Ulrica, exist still in part in the 

 Museum of the Upsala University. — Prof. Nordenskjbld spoke 

 on the inland ice of Greenland, and on the mineral dust found 

 on the same. — Prof. Torell exhibited a geological map of the 

 southern part of Sweden, published by the Geological Survey of 

 Sweden, and also a map of the northern part, delineated at the 

 same institution. He also described other geological maps of 

 Sweden. — Prof. Smitt reviewed the travels of Dr. Emil Riebeck 

 in Asia and Africa, and communicated a paper by the Rev. F. 

 Ilammargren on the bleating-like sound of the common snipe. 

 — Prof. Wittrock communicated papers (1) by M. Henning, on 

 his travels in Ilerjeadalen with regard to its mycology ; (2) by 

 M. G. Lagerheim, on his algological researches in the province 

 of Bohus ; and (3) by M. C. J. Johansson, on Taphrina, Fr., 

 and the Swedish species of that genus. — The Secretary, Prof. 

 Lindhagen, presented the following papers, viz. : — New or im- 

 perfectly known Isopoda described by Dr. C. Borvallius ; on 

 the action of the dioxide of hydrogen on earths ; on the com- 

 binations of samarium ; and new researches on the combinations 

 of didymium, all by Prof. P. T. Cleve of Upsala. 



CONTENTS Page 



Sir Henry Cole. By Rev. Newton Price 309 



Earthquakes and Fire-damp. By W. Galloway . . 312 



Magneto- and Dynamo-Electric Machines .... 313 

 Our Book Shelf:— 



Murphy's " Key to Magnus's Class-Book of Hydro- 

 statics and Pneumatics " 314 



Wormell's "Electrical Units" 314 



Milne's " Weekly Problem Papers " 314 



Letters to the Editor :— ' 



Free Hydrogen in Comets. — Prof. C. Piazzi Smyth 314 

 Iridescent Clouds.— Prof. W. G. Brown ; Prof. C. 



Piazzi Smyth 315 



Manx Cats. — George J. Romanes, F.R.S. . . . 316 



Cross-Breeding Potatoes. — Worthington G. Smith 316 



Earthquake. — J. G. S. Anderson 316 



An Instance of " Protective Resemblance." — J. C. G. 316 



Hibernation. — K. Busk 317 



Our Future Clocks and Watches. — Edward L. 



Garbett 317 



The Life-History of the Lycopodisceae. By W. T. 



Thiselton Dyer, C.M.G., F.R.S 317 



John Gwyn Jeffreys 317 



Alexander Murray, CM. G 318 



Searles V. Wood 318 



A Sunshine Recorder By Prof. Herbert McLeod. 



(Illustrated) 3'9 



Notes 320 



Our Astronomical Column :— 



The Occultation of Aldebaran on February 22 . . . 322 



Variable Stars 3 22 



Wolf's Comet 3 2 2 



Tempel's Comet 323 



Astronomical Phenomena for the Week 1885, 



February 8-14 323 



Geographical Notes 323 



The Institution of Mechanical Engineers .... 324 

 The Influence of Direct Sunlight on Vegetation. By 



Dr. M. Buysman 3 2 4 



New Organic Spectra. [Illustrated) 326 



South Georgia 3 2 7 



Cartographical Work in Russia 328 



Scientific Serials 328 



Societies and Academies 3 2 ^ 



