•I.^NCABT 1, 19(X).] 



KNOWLEDGE 



.t^ovrLEOqv, 



^ ILLUSTRATED MAGAZINE <if 



SCIENCE, LtTERATURE ^ARIV" 



Founded by RICHARD A. PROCTOR. 



LONDON: JAXIAUY 1, 190u. 



CONTENTS. 



. Bacon, f.r.a.s. 

 FT. W. Peauson, 



By R. 



HOWAKD a. ],ITTLE 



By Wm. Andeeson, 



Mid-Aip Observations. 

 {Illustrate,!) 



Plants and their Food. 



B.A.(CANTAB.) (I llustraleJ) 

 Explosions in Coal Mines. Uy John Mills. 

 The Natives of Australia and their Origin 



l.VDKKKEli. (IllHstrilleii) 



Photographs of Male and Female West Australian 

 Natives. (Plate). 



Astronomy without a Telescope. — I. Introduction. 



By Y.. WaLTEB ilAUNDER, F.R.A.S. 



The Constituents of the Sun. Bv .V. Fowler, f.e.a.s. 

 (Illustrated) 



'•Trees Strucl< by Lightning." By 



Letters : 



Is THE Stellar Uni verse Finite ? 



and E. J. Connell 

 AciD3 IN Soil. By W. A. Smith 

 Obituary : 



Sir J. William Dawson 



Sir Henry Tate 



Science Notes ... 



Notices of Books 



Books Receited 



The Black Rain of August 6 



Eddie, p.r.a.3. (Illustrated) 

 British Ornithological Notes. 



WiTHBBBY, F.Z.3.. M.B.G.tT. ... 



Microscopy. By John H. Cooke, p.l.s., p.o.8. (Illustrated) 



Notes on Comets and Meteors. By W. F. Dbnnino, 

 P.E.A.B 



The Face of the Sky for January, ^y A. Fowler, f.e.a.s. 



Chess Column. By C. D. Locock, b.a 



1899. By Major L. A. 

 Conducted by Habby F. 



II 

 13 



14 

 l(i 



16 

 16 



17 

 17 

 19 



19 



21 

 21 



22 

 2:i 

 23 



MID-AIR OBSERVATIONS. 



By John M. Bacon, f.e.a.s. 

 O.v carefully comparing the notes made by my 

 daughter and myself on the morning when the Leonid 

 shower was expected to be in progress, a few points of 

 scientific interest have been brought out which may be 

 worth recording, although having but little bearing on 

 astronomy. It may perhaps be claimed that their value 

 should be all the greater from the fact that the cir- 

 cumstances of our position as aerial observers, compelled 

 by a strange chance to remain aloft for many hours, 

 enabled us to give mature and undivided attention to 

 the few principal facts which I proceed to detail. 



Our actual view of such Leonids as were visible was 

 undoubtedly much enhanced by the exceptional advan- 

 tage we enjoyed of riding at 4,000 feet above any ground 

 surface, and, moreover, riding with the air currents. 

 Sufficient proof of this lay in the fact that the stars 

 from every quarter shone out of a black sky with a 



brilliance and definition never equalled in my ex- 

 perience, save on a former occasion when I made an 

 equally elevated night voyage. The altitude of the 

 radiant at the time of our ascent being about sixty 

 degrees, the body of the Balloon would hido such 

 meteors as shot upward, but, among those seen, one at 

 least was remarkable for its long-lasting trail, while at 

 another time a burst of three or four, darling in twist- 

 ing courses towards Orion, presented a peculiar phe- 

 nomenon such as I cannot recall, resembling a small 

 discharge of tailed stars from a rocket head. The un- 

 usual and persistently blue colour of Sirius was very 

 noteworthy. Though its hue constantly changed, it 

 could never have been described as possessing any other 

 colour than blue. 



Still more remarkable however was the "reen-grey 

 colour of the dawn. This shade was evanescent but 

 for the while strikingly noticeable, and corresponded 

 with su('li dawns as were much more pronounced and 

 long-lasting at the period foHowing the eruption of 

 Krakatoa in 1883. It becomes a question whether, 

 paucity of visible meteors notwithstanding, there may 

 not have been some unusual proportion of cosmic debris 

 intercepted by the upper strata of the atmosphere as 

 the earth crossed the track of the main Leonid stream. 



Though the official time of sunrise on this morning 

 was not till 7.21, it was two or three minutes before 

 six when with us the dawn began to break, and this 

 with a rapidity which I have not seen surpassed even 

 in India. To explain this latter phenomenon I would 

 suggest a double cause. First, that low-lying matter 

 and moisture in suspension, capable of reflecting and 

 diffusing light (and thus of anticipating dawn), had in 

 great measure been surmounted; and, secondly, that 

 as soon as appreciable light appeared its intensity was 

 redoubled by reflection off the brilliantly glistening 

 snow-surface below us. The cloud-veil here spoken of 

 had been first entered at an altitude of 1,500 feet, and 

 proved to be some 1,600 feet in thickness, and its ther- 

 mal conditions were sufficiently remarkable. 



Owing to the rapidity of our ascent, the temperature 

 of the lower levels was not accurately taken, but though 

 when we left the ground the night was one of except- 

 ional mildness for November, entering the cloud layer 

 struck us like passing into a warm greenhouse atmo- 

 sphere, and its temperature certainly cannot have been 

 less than 50 degrees. The upper ifringo of the same 

 cloud, however, tested accurately by a sling thermo- 

 meter, showed a temperature of 38 degrees, while at a 

 full thousand feet above in the clear open sky the same 

 thermometer showed a reading 4 degrees higher. The 

 Balloon gathered an extraordinary weight of condensed 

 moisture necessitating the discharge of many bags of 

 ballast, and all objects about us became rapidly and 

 densely dewed ; yet, at the upper surface where billows 

 of mist, mountains high, were surging and vanishing 

 into space, evaporations must have been going forward 

 very briskly, the super-incumbent air being doubtless 

 comparatively dry. It was just at the wasting upper 

 fringe of the cloud that the sensation (unusual in a free 

 balloon) of constant draughts was experienced, and this 

 experience was repeated whensoever wo dropped or 

 rose into this particular region. 



For the first hour the balloon constantly rose and 

 fell with a strongly marked pendulous motion, owing 

 to it.s many struggles with the moist cloud-wreaths and 

 the continual discharge of sand; but, oscillations once 

 over, its perfect poise was remarkable and unexampled 

 in my own experience. The region iu which it then 



