140 THE ANTARCTIC MANUAL. 
In this way two sets of curves were obtained, consisting of three 
curves in still air and three in a fresh breeze. The results are not 
very concordant, for, although the scale of time is very open—one 
minute occupying 5 mm.—the temperature scale was very close, 1° 
occupying only 1mm. The object, however, of the table is to show 
what can be expected from an instrument of the kind in the measure- 
ment of changes of temperature. The results obtained in the open 
air would necessarily vary somewhat, because, although a fresh breeze 
was blowing all the time, a fresh breeze varies in velocity. 
In order to obtain the best results from a thermometer, it should 
be exposed to uniform ventilation. This can only be effected by 
TaBLe XVI, GiviINc THE TimE In SECONDS REQUIRED BY a RicHARD’s RECORDING 
THERMOMETER TO OHANGE ITs TEMPERATURE BY 1° C. FOR A GIVEN DIFFERENCB 
or TEMPERATURE BETWEEN IT AND THE AIR. 
Difference of temperature 
between thermometer and 
air at beginning of 12°.) 11°.) 10%) BS.) BF | 1 G8, 5°, a 3°. 2°. 
exposure. 
In the 20" 20"| 25” 25"| 30”) 30”! 30” 65” 90” 90” | 240” 
as 
ao 
“Oo and ow [owe | we | we | . | 85 |] 45 | 120 | 130 | 150 | 300 
Be, fresh 
mo breezes. Si ac: fae a «. | 20 | 35 40 45 80 240 
om 
cam Mean from \\5, | oo |, | on | oo | on | on 
Bie | aye } 20 22 | 24 | 26 | 28 | 30| 35) 52 | 84 | 140 | 250 
o es ee Ree ae 
ot 
soe ie 60 | 70 110 130 | 210 
Ses In still 
sue air in ce [ee [ oe | ae Jove fee fe. | 90 | 100 | 300 | 450 
ato a room. 
“ee 120 | 160 | 300 
ao 
Bae sone ane (noe eeu ene oar es 
& \Mean . J .. | «. | «2 | we | ee |. | 60} 80 | 110 | 180 | 320 
artificial means, and they necessarily tend to efface sharp variations 
of temperature. 
Departing from the mercurial thermometer the writer has found 
the simple air thermometer very good for indicating and measuring 
quick variations of temperature. It has the advantage of lightness 
and cheapness. The form which I use is a glass bulb, of about 
3 cm. diameter on a straight stem of about 10 cm. length. This can 
be attached to a U-tube of greater or less diameter, according as the 
differences of temperature to be observed are great or small. The 
U-tube has some coloured water as indicator, and the indications of 
the instrument are compared with those of a thermometer. As the 
instrument is only put together when it is wanted, the variations of 
