608 
PROFESSOR FORBES ON THE TEMPERATURES 
is 60 litres per minute. The Grand Bain is at the extremity of the upper part of the 
great building. — 3. The Bain Ramond rises in the ancient Roman basin, and was only 
discovered within a few years. Discharges 21 litres per minute, and much gas. It 
is on the ground floor. — 4. Bain Rigny, near the last ; it formerly supplied a Roman 
piscina, and rises now into a small deep square cistern, discharging much gas, and 
18^ litres per minute. — 5. Source de la Madelaine. This spring is stated to be nearly 
destitute of any foreign ingredient except carbonic acid. It issues in an exceedingly 
copious spring at the base of a stone pillar which marks its source, which is at a 
lower level than the preceding ones, and exterior to the building. Discharges 102 
litres per minute. 
C. Temperature . — Elevation above the sea, 3425 feet. These springs, excepting the 
Grand Bain (for reasons already stated), seem to be extremely well adapted for ascer- 
taining the constancy of temperature of hot springs. We must recollect, however, 
that from the purely volcanic character of the district, changes in temperature may 
possibly depend upon causes merely local. Dr. Bertrand, the Inspecting Physician, 
states expressly that their temperature is invariable throughout the year. 
The following are my determinations. 
835 , September 16, 5 h p.m. 
-G 
£ 
O 
w 
O 
■ 4 — ’ 
- 4 —' 
u 
o 
£ 
s 
o 
Pm 
Cesar ..... 
Grand Bain. 
f_ _ , r Hottest part 
No. 1. < „ 1 
L Coldest part 
No. 2. In the middle 
f Middle . 
i N0 - 3 ' { Front . 
I ("Middle . 
N ° -4 ' { Front . 
No. 5. Hottest part 
Bain Ramond . . 
Bain Rigny .... 
Source de la Madelaine 
Thoughton. 
108' 1 
105-4 
105- 2 
106- 7 
108-0 
108'0 
104-3 
104-2 
103-5 
107*2 
108-2 
1110 
Reduced. 
108-0 
105-2 
105- 0 
106- 5 
107*9 
107*9 
104-1 
104-0 
1033 
107*1 
108-1 
110-9 
II. Bourboule les Bains. 
A. Geological Position.— The little village of Bourboule is situated in the group of 
Monts Dor on the right bank of the Dordogne, three or four miles below the Bains 
du Mont-Dor. The neighbouring rock is entirely a volcanic tufa, similar to that of 
Naples, and like it excavated, and these excavations used as dwellings. It is from 
the tufa that the springs rise. 
* No. 3 is the centre bath ; the temperature, it will be observed, regularly decreases on either hand. 
