160 Notes and Memoranda. 



bank in the south. I supposed the appearance above described to have been the 

 Aurora Australis ; but the captain and officers of the ship, as well as those passen- 

 gers who have been living in the southern hemisphere, all said that they had 

 never seen anything like it before, and that all the auroras which they had seen 

 showed bright lights of many different colours, constantly shifting, but never this 

 steady pale light. — [It must have been an exhibition of the aurora : the colours 

 often seen are not essential to the phenomenon]. — Mr. Alexander S. Herschel, to 

 whom the above description was shown, has kindly sent the following account of 

 a somewhat similar appearance, described by Dr. J. D< Hooker, Himalayan 

 Journals, large 8vo edition, vol. ii. p. 385 : — " 1848, Feb. 14, nine p.m. Baroon 

 (east bank of the Soane Eiver, lat. 24° 52' N., long. 84^ 22' E., alt. 345 feet, bar. 

 corr. 29"751, temp. 62°, dew point 41°0. -Calm, sky clear, moon f full, and so bright 

 that the milky-way and zodiacal light could not be discerned, and the stars and 

 planets were very pale). Observed about thirty lancet beams rising in the north- 

 west, from a low luminous arch, whose extremes bore W. 20° S., and N . 50° E.; 

 altitude of upper limb of arch, 20° ; of the lower, 8°. The beams crossed the 

 zenith, and converged towards S. 15° E. The extremity of the largest was forked, 

 and extended to 25" above the horizon in the S.E. by S. quarter. The extremity 

 of the centre one bore S. 50 3 E., and was 45° above the horizon. The western 

 beams approached nearest the southern horizon. All the beams moved and 

 flashed slowly, occasionally splitting and forking, fading and brightening. They 

 were brightly defined. At ten p.m. the luminous appearance was more diffused. 

 !No beam crossed the zeinth, but occasionally beams appeared there and faded 

 away. Between ten and eleven the beams disappeared from the S.E. quarter, and 

 the longest and broadest beams were near the N. and U.E. horizon. Those who 

 were witnesses of the appearance considered it a brilliant display of the aurora." 

 Mr. Herschel observes that in this case the beams ruled the sky from N.IT.W. to 

 S.S.E., and nearly from horizon to horizon : i.e. nearly north and south, and 

 nearly horizontal, which is an uncommon appearance. 



Temperature and Development. — M. Dareste has communicated to the 

 French Academy the results of experiments on the development of embryos in 

 fowls' eggs, at comparatively low temperatures. He finds that the germ does not 

 become an embryo below 30 3 C. or 86 1 F. Embryos formed between 30" 1 and 34" 

 C. grow very slowly, and none are hatched. Many of the embryos became mon- 

 strous, some presenting anomalies in the head, others were like cyclops, and these 

 often exhibited two rudimentary hearts. 



Stool eor Astronomers and Artists. — In using telescopes of three or four 

 inches aperture, mounted at 5| or 6 feet from the ground, a great many objects 

 are conveniently seen when the observer is seated on a firm stool capable of ad- 

 justment, varying its height from 19 to 31 inches. For this purpose, Mr. Slack 

 has had a stool constructed of oak, well dovetailed together. It consists of two 

 parts. The outer part, 18i inches high and 11 by 13 wide, is like an oblong box, 

 open at top and bottom. Into this slides a similar box, closed at the top by a seat 

 slightly overhanging the sides, and half an inch thick. On opposite sides of the 

 outer part are cut two slits three-eighths of an inch deep, and three inches wide. 

 These slits are two and a half inches below the top, and exactly correspond with 

 each other. On opposite sides of the inner parts there are two sets of slits of the 

 same dimensions. Each set contains thirteen slits, and when the inner part is 

 dropped down as far as it will go, a, bar of oak three-eighths of an inch thick, and 

 three inches wide, passes from side to side through the two outer slits, and through 

 the top slits of the inner sets. From centre to centre, the inner slits are one inch 

 apart, and when the stand has to be raised, the slide is pulled out and pushed in 

 again through the slits, which correspond with the elevation required. A little 

 practice enables this to be done in a moment, even in the dark, and the stool is 

 quite firm at its greatest elevation. A stool of this kind must be thoroughly well 

 made, or it would be a ricketty, troublesome affair. The one described, made by a 

 first-rate workman, cost 35s., and has been in use for several months, leaving 

 nothing to be desired. It is evident that a stool of the same description would often 

 be very convenient for artists. 



