128 
MR. J. R. CHRISTIE ON THE USE OF THE BAROMETRIC 
of those expressing the two component heights, arrive at an expression for the inter- 
mediate boiling-point in terms of the atmospheric temperatures at the three stations 
and the upper and lower boiling-points ; such an expression is 
b"= | • b'+ b'"+ 8-4 j 
where T, t and T' are the temperatures at the stations where the boiling-points are 
respectively b', b" and b '" ; but this, when put in the form 
,„__23 f t.(b'-b<«)+Tb"'-T'b< . 
0 — 24 l T— T' 
shows us that an error in the value of t, of trifling moment where that value is to be 
employed in the determination of the difference of level, will cause an error in the 
resulting boiling temperature of very serious amount when used for the same purpose. 
Though this test cannot therefore be made use of in its full rigour, it will be highly 
satisfactory if an accordance can be shown between the results above referred 
to: the following, Table II., exhibits a comparison of these values. The numbers in 
the second column are the differences of the boiling temperatures, in degrees of 
Fahrenheit, deduced from the barometric observations at Geneva and the Great St. 
Bernard, which were simultaneous with those of my own made at the places named 
in the first column. 
Table II. 
Station. 
Difference of boiling- 
points derived from 
the observations at 
Geneva and the Great 
St. Bernard. 
.5 
*o £ 
ii ^ 
'rt 
> 
Derived difference 
of height. 
Difference of height 
from Table I. 
Station. 
Difference of boiling- 
points derived from 
the observations at 
Geneva and the Great 
St. Bernard. 
Value of (t— 32°) in 
formula II. 
Derived difference 
of height. 
Difference of height 
from Table I. 
Les Rousses 
Geneva 
Bonneville 
Mole 
St. Jeoire 
Samoens 
Col Diehaud 
Servoz 
Chamounix — 1 
Chamounix — 2. 
Chamounix — 3 
Montanvert 
Contamines — 1 
Contamines — 2 
Croix du Bonhomme 
Chapin — l 
Chapiu — 2 
Bourg St. Maurice 
llospice Pt. St. Bernard 
Cormayeur — 1 
Cormayeur — 2 
Cormayeur — 3 
Aosta — 1 
Aosta — 2 
Aosta — 3 
Aosta — 4 
Aosta — 5 
St. Remy 
Great St. Bernard — 1 
Great St. Bernard — 2 
St. Vincent — 1 
St. Vincent — 2 
11-583 
11-856 
11-794 
11-832 
11-936 
11-813 
11-834 
1 1-781 
11-568 
11-593 
11-491 
11-699 
11-811 
11- 748 
11-828 
12061 
12- 005 
11-642 
11-748 
11-953 
11-861 
11-809 
11- 997 
12- 060 
12-102 
11-895 
11-976 
11911 
11-873 
11-795 
11-930 
22-8 
25-3 
21- 4 
20-9 
17- 6 
28-1 
12-6 
27- 3 
20- 5 
22 2 
28- 6 
22- 3 
19 7 
25-6 
170 
16-9 
1 6-0 
28-7 
25-6 
15-4 
271 
25-3 
13-0 
15- 9 
13-2 
24-3 
16 2 
18- 1 
21- 3 
16- 5 
20-5 
6669 
6862 
6768 
6784 
6796 
6877 
6666 
6846 
6627 
6664 
6696 
6728 
6755 
6803 
6726 
6857 
6811 
6786 
6803 
6775 
6852 
6835 
6785 
6842 
6806 
6835 
6798 
6790 
6816 
6715 
6835 
6668 
6792 
6820 
6810 
6776 
6764 
6919 
6742 
6869 
6739 
6747 
6750 
6767 
6866 
6825 
6772 
6880 
6829 
6775 
6777 
6815 
6796 
6876 
6786 
6904 
6798 
6903 
6841 
6791 
6753 
6731 
6615 
Col de Jou 
Brussone 
Col Ranzola 
Gressonay— 1 
Gressonay — 2 
Gressonay — 3 
Col di Val Dobhia 
La Riva — 1 
La Riva — 2 
Varallo — 1 
Varallo— 2 
La Colma 
Orta — 1 
Orta — 2 
Orta — 3 
Mogadino — 1. .. 
Mogadino — 2 
Dotno d’Ossola — 1 
Dorno d’Ossola — 2 
Simplon Village 
Simplon Hospice 
Brieg — 1 
Brieg — 2 
Leukerbad — 1 
Leukerbad — 2 
South Crest of the Gemmi ... 
Ivandersteg — 1 
Kandersteg — 2 
Lauterbrunnen — 1 
Lauterbrunnen — 2 
Bern 
11-860 
11-372 
11-716 
11- 789 
11-818 
12- 003 
11-964 
11-851 
11-729 
11-640 
11-646 
11-574 
11-578 
11-661 
11-782 
11-805 
11-748 
11-764 
11-865 
11-936 
1 1- 933 
12- 038 
12-121 
12020 
12-014 
11-950 
11-828 
11-823 
11-700 
11-749 
11-641 
24-1 
270 
29-0 
20-0 
220 
17- 5 
20-0 
16- 5 
22- 5 
24- 7 
23- 6 
26-8 
270 
25- 7 
21- 3 
22 1 
21-6 
20-9 
18- 5 
220 
20-9 
11- 7 
12- 4 
12-1 
14-2 
22- 0 
17- 4 
22-6 
22-9 
251 
30T 
6847 
6605 
6833 
6719 
6763 
6833 
6847 
6735 
6749 
6728 
6716 
6860 
6725 
6758 
6761 
6786 
6746 
6746 
6762 
6859 
6842 
6768 
6826 
6763 
6790 
6868 
6731 
6804 
6737 
6797 
6805 
6855 
6644 
6855 
6905 
6816 
7046 
6964 
6793 
6727 
6718 
6680 
6823 
6726 
6707 
6771 
6839 
6742 
6829 
6808 
6881 
6837 
6835 
6746 
6777 
6774 
6855 
6738 
6737 
6697 
6699 
6801 
