34 



NATURE 



{_May 13, 1880 



o'oooooooi inillim., exiiibits deductions from actual 

 observations : — 



It is conceivable that the aurora may occur at times at 

 an altitude of a few thousand feet. 



The following- letter has been sent us in reference to the 

 above paper : — 



Meteorological Office, 1 1 6, Victoria Street, 



London, S.W., May i, 1880 



With reference to a paper at the Royal Society on the 

 height of auroras by Dr. De la Rue and Dr. Miiller, the fol- 

 lowing rei-i-iarks in Miiller's " Lehrbuch der kosmischen 

 Physik," 2nd Edition, 1S65, p. 558, may be of interest to 

 5'our readers :— 



" Hansteen finds for the aurora of January 7, 1831, a 

 height of 26 geographical miles, by combining the height 

 of thearch at Berlin and Christiansand in Norway, while 

 Christie calculates the height of the same aurora at 

 between 5 and 25 English miles, from observations made 

 in England. 



"The determinations of modern physicists place the 

 aurora at a much lower level than was formerly assumed. 

 Mairan gave the mean height at 120, Cavendish (1790) at 

 60, and Dalton (1S28) at only 18 geographical miles. 



"Farquharson makes it probable that the auroras, as 

 was already said by Baron v. Wrangell, come down to the 

 region of the clouds. He bases this, inter alia, upon the 

 auroral observations of December 20, 1829. At .Alford, 

 in Aberdeenshire, he saw, from 8.30 to 11 o'clock in the 

 evening, a very brilliant aurora over a thick mass of clouds 

 which covered the hills lying to the north of his house. 

 Although the sky w-as clear the aurora never rose higher 

 than 20^. At the same time the Rev. Mr. Paul), at 

 Tullynessle, lying two English miles north of Alford, in 

 a narrow side valley of the hills above mentioned, saw a 

 very brilliant aurora close to the zenith about 9.15. This 

 would give the height of the aurora as not more than 

 4,000 feet. This opinion is confirmed by numerous ob- 

 servations made in the Polar regions by Parry, Franklin, 

 Hood, and Richardson. Franklin observed auroras 

 between the clouds and the earth, which lit up the lower 

 surface of thick clouds. 



" So much is certain, the phenomenon appears in 

 various heights, but can hardly be seen higher than 

 twenty miles. The auroras formed at low heights, which 

 are often seen in the Polar regions, are only visible at 

 short distances. Hood quotes an aurora on April 2, 1820, 

 at Cumberland House, as a brilliant arch of 10° altitude. 

 Fifty-five English miles to the south-west nothing w-as 

 visible. 



"Another aurora on April 6, which remained in the 

 zenith for some hours over Cumberland House, appeared 

 at the distance ol 100 English miles to the south-west as 

 a steady arch only 9-^ in height." 



The ob,ervation of Mr. Smith of Jordan Hill, at Loch 

 Scavaig in Skye, of an aurora apparently emanating from 

 a mountain there, will also be remembered. 



Robert H. Scott 



A SCOTTISH CRANNOG^ 

 W.— Objects of Bone 

 1 JPWARDS of twenty implements made of bone have 

 *-^ been added to the general collection, all of which 

 were found either in the relic bed or refuse heap. The 

 following are the most interesting. 



I. Two chisels or spatulas. One is made of a split 

 portion of a shank bone, and measures si inches long 



Fig. 6.— Bene (Scale J.) Fig. 7.— Bone (Scale }) 



and rather less than \ inch broad. It is very hard, flat, 

 and smoothly ground at one end, and has a sharp rounded 

 edge, which e.xtends farther on the left side, thus indi- 

 cating that it was adapted for being used by the right 

 hand. The other is a small leg bone obliquely cut so as 

 to present a smooth polished surface. Its length is 

 4 inches, and its diameter \ inch. 



2. Five small objects presenting cut and polished 

 surfaces, three of which are sharp and pointed ; one 



i.— H>;rn (Scale !). 



Fig. 9.— Horn (Scale }). 



appears to have been notched at the end and there broken 

 olf ; and the last, presenting well-cut facets, is fashioned 

 into a neat little wedge. 



3. Fig. 6 represents a tiny little spoon only J inch in 

 diameter, and worn into a hole in its centre. The handle 

 portion is round and straight, and proportionately smallj 



'A full report of the Lcchke Crarnog is given in vol. xiii. of the 

 Proceedings ot the Society of Ant:quanes of Scotland, and in vol. ii. of the 

 Collections of the Ayrshire and Wigtownshire Archaological Association- 

 Continued from p. 16. 



