TRANSACTIONS OF SECTION A. 43% 
S.R. was 201'6. At 2.25 occurred the strangest combination in my record, 
for with the dry bulb at the fairly comfortable range or 45°7° the wet bulb showed 
30-6°, or was below the freezing point, and was accordingly coated with ice, while 
the black bulb showed 199°1°, or no less than 13° above 186:1°, the boiling point of 
water at Vincocaya. Respecting this same boiling point, perhaps I may be per- 
mitted to add a fact or two. An egg may be fairly lightly boiled in four and a half 
minutes, but twenty-four hours’ boiling will not suffice to cook dried beans. 
During the construction of the railway, digesters were used for cooking this article 
of food, which is greatly in vogue in South America ; but now that the digesters are 
worn out, beans can no longer be cooked at high altitudes. It is necessary to 
lengthen the chimneys of all the paraffin lamps by some six inches to get a flame 
devoid of smoke. It also takes a full hour longer to get up steam in a locomotive 
than at the sea-level. Of course temperature comes a little into play, but the 
diminution of air pressure is the main cause of these differences. A favourable 
chance of passing the blockade at all occurring unexpectedly, I left Vincocaya on 
June 27, and so had a mere glimpse of the sun, &c., at Arequipa on the 29th 
and 30th. S.R., 2054° to the very top of tube; tension, 0°139in., 19°3 %. Now 
if we consider what is the best height and situation in which to place an obser- 
vatory that it might be intended to maintain for a few years, I should recommend 
an eleyation of some 9,000 to 12,000 ft. My own measures go to show that an 
increase of height of 150 ft. reduces the night temperature by about 1° Fahr. 
Now at 12,500ft. on the clear nights there is almost always a certain amount of frost, so 
that for any greater altitude it is very easy to find the cold to which the observer 
would be exposed. It should be noted, too, that the cold is much more unpleasant 
to bear ina thin atmosphere than down at the sea-level. In a thin atmosphere, 
too, all exertion becomes fatiguing, and in particular that of moving about under 
a load of heavy garments. At considerable altitudes, I need hardly say, a given 
change of elevation affects the density of the air by only a comparatively small 
quantity—e.e. at Puno, as we have seen, the barometer stands at 18-7, for 
12,540 ft. At Vincocaya we have 17°6, for 14,360 ft. At the lower station we 
have the potato cultivated in a hundred varieties, along with maize, &c., while 
at the upper one all horticulture is utterly impracticable, and barley even only 
yields a few green blades. This total change im the vegetable world is due to 
a decrease of mean temperature of about 13° Fahr. On the ground, therefore, of 
mere comfort and facility of work a station higher than Puno is not to be recom~ 
mended for anything like permanent occupation. On the other hand it would be 
yery valuable if a higher elevation could be commanded for a few months in the 
more favourable season, say from the beginning of October until the middle 
of December. At that season a station 18,500 ft. high might be occupied without 
serious inconvenience, and in Peru there would be the advantage of a practically 
vertical sun every day. This view is based on the fact that Dr. Falb and a gentle-- 
inan whom I met repeatedly had spent several days on the summit of the Misti 
volcano (18,650 ft.) at the season just mentioned. I do not mean to say that the- 
top of the Misti would be likely to be a good site, but in the neighbourhood of 
Puno, Santa Rosa, or of La Paz, or, in fact, almost anywhere in the neighbourhood 
of Lake Titicaca, a very favourable spot might be found for such an extra elevated 
station. 
6. On some points in Lemstrim’s recent Auroral Lxperiments in 
Lapland. By J. Ranp Carron. 
The existing sun-spot epoch augurs well for the advent of auroral displays in the 
coming winter, while the recent experiments of Prof. Lemstrém in Lapland have 
brought this interesting phenomenon prominently before the public mind. The author 
does not propose on this occasion to discuss the results of these experiments beyond - 
pointing out that they can hardly be accepted in their present state as conclusive. 
Amonz the obscure points may be mentioned the want of any actual recorded 
measurement of the line considered to be recognised as the ‘citron’ auroral line; 
certain discrepancies which appear on comparing the discharges, or rather eollections, . 
