When Miss Bird spent a night on the summit of Mauna Loa during the eruption of June, 1874, the cold was described as intense, eleven degrees of frost (21° F.).

Observations on the Summit of Mauna Kea.—.... When Prof. Alexander with a party of scientists ascended this mountain (in the summer of 1892), the thermometer at night fell to 13° F., and the trade-wind was found to be blowing as strongly on the summit as down below (Whitney’s Tourist Guide to Hawaii). It is to be inferred that the party camped by the small lake which is a few hundred feet below the actual summit (13,800 feet). This lake, which I visited on May 20, 1897, is about 120 yards across, and evidently shallow, probably not more than three or four fathoms deep. A carpet of algæ covered the bottom. At noon, by the lake, the air in the shade was 53° F., whilst the temperature of the surface-water was 51°. The lower clouds were moving from S.S.E. This lake is said to be permanently frozen over in the winter, and to have been visited by skaters.

Permanent Water Supply on the Summit of Mauna Loa.—In this barren rocky region water derived from the winter-snow is to be found all the year through at the bottom of the deep cracks or fissures in the lava-rock. Such fissures are from two to four feet wide, and in the case of that near my tent the bucket had to be lowered to a depth of seventeen or eighteen feet to reach the water, or rather the ice, since it was often necessary to break the surface ice. In these deep, narrow fissures, which the sun scarcely penetrates, the water would probably be frozen over all through the seasons; but in those of less depth it would remain liquid in summer.

Register of Observations on Wind, Relative Humidity, Cloud, Rain, and Temperature, made by H. B. Guppy on the Summit of Mauna Loa at an Elevation of 13,500 Feet above the Sea, August 9th to 31st, 1897. (Camp about Middle of West Side of Crater Margin)

Date.Observation.12-4 A.M.4-8 A.M.8-12 A.M.12-4 P.M.4-8 P.M.8-12 P.M.Air in shade.Remarks.
Min.Max.Range.
9WindS.S.W-S.W. 2Variable...W.S.W.-W.N.W. 3N.N.W.-N. 1N.N.W.-N. 3F.F.F.A beautifully coloured lunar halo at 1 A.M. Electrical condition of the atmosphere (see text).
Rel. hum...................27·561·233·7
Cloud000000
Rain000000
10Wind...N.N.W. 2S.S.W.-W.S.W. 3S.S.W.-W.S.W. 2Calm... Electrical condition of the atmosphere. Faint lunar halo at 8 P.M.
Rel. hum.......3442·546...33·559·726·2
Cloud...0120...
Rain000000
11WindCalm W.S.W. 1......S.S.W.-S.W. 1 ... Electrical condition of the atmosphere.
Rel. hum....... 28·5......... 22·561·238·7
21
Cloud00010...
Rain 000000
12WindCalmCalmN.N.W.-N. 2-3N.N.W. 1N.N.W.-N. 2-4N. 2-4, S.W.-W.S.W. 3-5 Earth tremors. Total rain, 10⁄100. At sunset, wind N.W., wet canvas of tent froze hard. At 10 P.M., strong southerly wind, canvas thawed, rain with strong gusty wind until 4 A.M., when wind less.
Rel. hum.......457989...2354·731·7
Cloud00510105
Rain000RainRainRain
13WindS.W. 4-6S.W. 3-5S.W.-S.S.E. 3-4S.W. 3Calm; N.W. 1... Earth tremors. Total rain 10⁄100.
Rel. hum.......868678... 33·648·715·1
Cloud...107109...
RainRainRain0RainRain0
14WindN.N.W.-N. 1Northerly, 3N.N.W. 3N.N.W. 2N.N.W. 1... Butterflies flying about in a semi-torpid state, and easily caught with the hand.
Rel. hum....61·5474245·5... 32·552·219·7
Cloud3000-20...
Rain000000
15WindNortherly, 1W.S.W. 1, N.N.W. 1S.W.-W. 2Calm; Southerly, 1Calm; N.N.W. 1N.N.E.-1-2 Wind fitful during day; north-westerly and south-westerly airs with calms.
Rel. hum.......3844·5 62... 2854·726·7
52·5
Cloud 00077-00
Rain000000
16WindCalmN.N.W. 2N. 3...Southerly, 1... Carefully observed the shadow of the mountain which, at sunrise and sunset, is projected against the opposite horizon.
Rel. hum....... 32 ...61... 2653.227.2
28
Cloud...0070...
Rain000000
17Wind...N.N.W. 1N.N.W. 2, Southerly, 2N.-N.N.E 3, Southerly, 2N.N.W. 1... Fitful northerly and southerly winds causing miniature whirlwinds that carried dust and paper up into the air.
Rel. hum.......3232·5...... 20·558·738·2
Cloud...0010...
Rain000000
18WindCalmS.W. 1Variable ...S.W. 2... —
Rel. hum.......26...47... 235835
Cloud00010...
Rain000000
19Wind......N.N.W. 1, W.S.W. 1Northerly, 3, S.S.W. 3Northerly, 2, Southerly, 2Southerly, 3 Through the day, fitful northerly and southerly breezes.
Rel. hum.......2023 24 ... 2258·736·7
35·5
Cloud......0000
Rain000000
20WindSoutherly, 2Northerly, 1, Southerly, 1Northerly, 1, Southerly, 1S.S.W.-S.W. 4Northerly, 2, Southerly, 1Southerly, 3 Fitful northerly and southerly airs, often reversing several times in a few minutes.
Rel. hum.......26·52529·5... 2257·235·2
Cloud000000
Rain000000
21WindSoutherly, 4Southerly, 3-4S.S.W. 3-4S.S.W. 4-5S.W. 4-5S.W. 4 At camp, strong southerly winds all day. At 7 A.M., walked half-mile north and found a bitterly cold N.N.E. gale blowing there, which forced me to return to camp where the south wind still blew freshly.
Rel. hum.......35·53147... 26·553·727·2
Cloud...0000...
Rain000000
22Wind...S.S.W. 1 ......Calm, Southerly, 2... Walked round the crater from 8 A.M. to 6 P.M.
Rel. hum.......58......... 20·546·726·2
Cloud...0010...
Rain000000
23Wind...S.S.W. 2...N.N.W.-N.E. 1-3, Southerly, 3Southerly, 1Calm A few drops of rain at 2 P.M.
Rel. hum....... 6052·5 70... 2450·726·7
54·564
Cloud ...033-83-60
Rain000Rain00
24 Wind...Northerly, 3S.W. 1N.N.W.-N. 2-3N.N.W.-N. b. E. 2-3Northerly 2
Rel. hum.......54·5...53... 2052·732·7
Cloud...00-140...
Rain000000
25WindCalm...Calms with N.W. and S.W. airsCalms with N.W. and S.W. airsNortherly and Southerly airsNortherly and Southerly airs A few drops of rain at 3 P.M.
Rel. hum....... 42·573·5 61... 1752·235·2
37·561·5
Cloud000-12-900
Rain000Rain00
26WindNortherly, 2N.N.W. 1...N.N.W.-N. 3N.N.W. 2... Descended through the bank of cumulus on S.W. slope and found driving mist coming up the slope from S.W.
Rel. hum.......49·5...64... 19·553·734·2
Cloud0...3300
Rain000000
27WindCalms with light airsCalms with light airsS.W.-W.S.W. 2W.S.W.-W. 1SoutherlyCalm Rain not measurable. Rain-clouds poured into and filled the huge crater.
Rel. hum.......3573·5...... 18·550·732·2
Cloud0041040
Rain000Rain00
28WindCalms with northerly airsCalms with variable airsN.N.W.-N. 2-3S.S.W. 3Northerly, 3Calms with variable airs 9 A.M., high stationary cirrus; at noon, solar halo; in afternoon, nimbus partly filling crater causing a rainbow there; a few drops of rain at 4 P.M.
Rel. hum....... 46·564·5 ...... 1549·734·7
59·073·0
Cloud005700
Rain000Rain00
29WindN.N.W.-N. 3N.N.W.-N. 2N.-N. b. E. 3N.N.W. 3, S.S.W. 2Calms with variable airsNortherly, 1
Rel. hum.......454460·5... 21·548·727·2
Cloud000000
Rain000000
30WindCalms with northerly airsSoutherly, 1N.N.W. 2-3N.N.W. 3Calms with variable airs...
Rel. hum.......32·5 41·0 ...... 1850·732·7
54·5
Cloud000000
Rain000000
31.....................18·550·031·5
Date.Observation.12-4 A.M.4-8 A.M.8-12 A.M.
9WindS.S.W-S.W. 2Variable...
Rel. hum..........
Cloud000
Rain000
10Wind...N.N.W. 2S.S.W.-W.S.W. 3
Rel. hum.......34
Cloud...01
Rain000
11WindCalm W.S.W. 1...
Rel. hum....... 28·5
21
Cloud000
Rain 000
12WindCalmCalmN.N.W.-N. 2-3
Rel. hum.......45
Cloud005
Rain000
13WindS.W. 4-6S.W. 3-5S.W.-S.S.E. 3-4
Rel. hum.......86
Cloud...107
RainRainRain0
14WindN.N.W.-N. 1Northerly, 3N.N.W. 3
Rel. hum....61·547
Cloud300
Rain000
15WindNortherly, 1W.S.W. 1, N.N.W. 1S.W.-W. 2
Rel. hum.......38
Cloud 000
Rain000
16WindCalmN.N.W. 2N. 3
Rel. hum....... 32
28
Cloud...00
Rain000
17Wind...N.N.W. 1N.N.W. 2, Southerly, 2
Rel. hum.......32
Cloud...00
Rain000
18WindCalmS.W. 1Variable
Rel. hum.......26
Cloud000
Rain000
19Wind......N.N.W. 1, W.S.W. 1
Rel. hum.......20
Cloud......0
Rain000
20WindSoutherly, 2Northerly, 1, Southerly, 1Northerly, 1, Southerly, 1
Rel. hum.......26·5
Cloud000
Rain000
21WindSoutherly, 4Southerly, 3-4S.S.W. 3-4
Rel. hum.......35·5
Cloud...00
Rain000
22Wind...S.S.W. 1 ...
Rel. hum.......58
Cloud...00
Rain000
23Wind...S.S.W. 2...
Rel. hum....... 60
54·5
Cloud ...03
Rain000
24 Wind...Northerly, 3S.W. 1
Rel. hum.......54·5
Cloud...00-1
Rain000
25WindCalm...Calms with N.W. and S.W. airs
Rel. hum....... 42·5
37·5
Cloud000-1
Rain000
26WindNortherly, 2N.N.W. 1...
Rel. hum.......49·5
Cloud0...3
Rain000
27WindCalms with light airsCalms with light airsS.W.-W.S.W. 2
Rel. hum.......35
Cloud004
Rain000
28WindCalms with northerly airsCalms with variable airsN.N.W.-N. 2-3
Rel. hum....... 46·5
59·0
Cloud005
Rain000
29WindN.N.W.-N. 3N.N.W.-N. 2N.-N. b. E. 3
Rel. hum.......45
Cloud000
Rain000
30WindCalms with northerly airsSoutherly, 1N.N.W. 2-3
Rel. hum.......32·5
Cloud000
Rain000
31............
Date.Observation.12-4 P.M.4-8 P.M.8-12 P.M.
9WindW.S.W.-W.N.W. 3N.N.W.-N. 1N.N.W.-N. 3
Rel. hum..........
Cloud000
Rain000
10WindS.S.W.-W.S.W. 2Calm...
Rel. hum.42·546...
Cloud20...
Rain000
11Wind...S.S.W.-S.W. 1 ...
Rel. hum..........
Cloud10...
Rain 000
12WindN.N.W. 1N.N.W.-N. 2-4N. 2-4, S.W.-W.S.W. 3-5
Rel. hum.7989...
Cloud10105
RainRainRainRain
13WindS.W. 3Calm; N.W. 1...
Rel. hum.8678...
Cloud109...
RainRainRain0
14WindN.N.W. 2N.N.W. 1...
Rel. hum.4245·5...
Cloud0-20...
Rain000
15WindCalm; Southerly, 1Calm; N.N.W. 1N.N.E.-1-2
Rel. hum.44·5 62...
52·5
Cloud 77-00
Rain000
16Wind...Southerly, 1...
Rel. hum....61...
Cloud70...
Rain000
17WindN.-N.N.E 3, Southerly, 2N.N.W. 1...
Rel. hum.32·5......
Cloud10...
Rain000
18Wind...S.W. 2...
Rel. hum....47...
Cloud10...
Rain000
19WindNortherly, 3, S.S.W. 3Northerly, 2, Southerly, 2Southerly, 3
Rel. hum.23 24 ...
35·5
Cloud000
Rain000
20WindS.S.W.-S.W. 4Northerly, 2, Southerly, 1Southerly, 3
Rel. hum.2529·5...
Cloud000
Rain000
21WindS.S.W. 4-5S.W. 4-5S.W. 4
Rel. hum.3147...
Cloud00...
Rain000
22Wind...Calm, Southerly, 2...
Rel. hum..........
Cloud10...
Rain000
23WindN.N.W.-N.E. 1-3, Southerly, 3Southerly, 1Calm
Rel. hum.52·5 70...
64
Cloud 3-83-60
RainRain00
24 WindN.N.W.-N. 2-3N.N.W.-N. b. E. 2-3Northerly 2
Rel. hum....53...
Cloud40...
Rain000
25WindCalms with N.W. and S.W. airsNortherly and Southerly airsNortherly and Southerly airs
Rel. hum.73·5 61...
61·5
Cloud2-900
RainRain00
26WindN.N.W.-N. 3N.N.W. 2...
Rel. hum....64...
Cloud300
Rain000
27WindW.S.W.-W. 1SoutherlyCalm
Rel. hum.73·5......
Cloud1040
RainRain00
28WindS.S.W. 3Northerly, 3Calms with variable airs
Rel. hum.64·5 ......
73·0
Cloud700
RainRain00
29WindN.N.W. 3, S.S.W. 2Calms with variable airsNortherly, 1
Rel. hum.4460·5...
Cloud000
Rain000
30WindN.N.W. 3Calms with variable airs...
Rel. hum. 41·0 ......
54·5
Cloud000
Rain000
31............
Date.Air in shade.Remarks.
Min.Max.Range.
F.F.F.
927·561·233·7A beautifully coloured lunar halo at 1 A.M. Electrical condition of the atmosphere (see text).
1033·559·726·2Electrical condition of the atmosphere. Faint lunar halo at 8 P.M.
1122·561·238·7Electrical condition of the atmosphere.
122354·731·7Earth tremors. Total rain, 10⁄100. At sunset, wind N.W., wet canvas of tent froze hard. At 10 P.M., strong southerly wind, canvas thawed, rain with strong gusty wind until 4 A.M., when wind less.
1333·648·715·1Earth tremors. Total rain 10⁄100.
1432·552·219·7Butterflies flying about in a semi-torpid state, and easily caught with the hand.
152854·726·7Wind fitful during day; north-westerly and south-westerly airs with calms.
162653.227.2Carefully observed the shadow of the mountain which, at sunrise and sunset, is projected against the opposite horizon.
1720·558·738·2Fitful northerly and southerly winds causing miniature whirlwinds that carried dust and paper up into the air.
18235835—
192258·736·7Through the day, fitful northerly and southerly breezes.
202257·235·2Fitful northerly and southerly airs, often reversing several times in a few minutes.
2126·553·727·2At camp, strong southerly winds all day. At 7 A.M., walked half-mile north and found a bitterly cold N.N.E. gale blowing there, which forced me to return to camp where the south wind still blew freshly.
2220·546·726·2Walked round the crater from 8 A.M. to 6 P.M.
232450·726·7A few drops of rain at 2 P.M.
24 2052·732·7
251752·235·2A few drops of rain at 3 P.M.
2619·553·734·2Descended through the bank of cumulus on S.W. slope and found driving mist coming up the slope from S.W.
2718·550·732·2Rain not measurable. Rain-clouds poured into and filled the huge crater.
281549·734·79 A.M., high stationary cirrus; at noon, solar halo; in afternoon, nimbus partly filling crater causing a rainbow there; a few drops of rain at 4 P.M.
2921·548·727·2
301850·732·7
3118·550·031·5

Method of Observation employed by the Author on the Summit of Mauna Loa.—My camp was placed near the middle of the west margin of the crater about 13,500 feet above the sea. The instruments employed were a Sixe’s maximum and minimum thermometer made by Negretti and Zambra, several unmounted thermometers, and a reference thermometer (with a Kew certificate) by the above-named makers, which was used as a standard. The freezing point was also tested for all the instruments on the summit in melting powdered ice. The maximum air observations and those on the relative humidity were taken in a small cave with a hole in the roof, through which there was a steady flow of air. One day was occupied in comparing the cave-observations with those obtained under a temporary screen rigged up outside my tent, the only difference shown being as a rule less than a degree. The minimum observations taken in my tent, where there was no artificial heat, were usually only 1·5° higher than those given by a thermometer outside the tent.

Results of the Observations on the Top of Mauna Loa, Aug. 9-31, 1897