456 DE, R. E. SCOEESBY- JACKSON ON THE TEMPERATURE 



were satisfied ; if they differed more than that, we repeated the observations, 

 sometimes three or four times; but often failed in the end to bring the two 

 nearer than within two or three tenths of a degree. Both observations are inva- 

 riably given in the descriptive remarks and in the tables. When the tempera- 

 ture was taken at a buvette, or other running stream, a large tumbler was placed 

 under the stream ; the water was allowed to flow into and over it for a minute or 

 two, until the glass assumed the temperature of the Avater as nearly as it could 

 be made to do ; the thermometers were then placed in the tumbler, and allowed 

 to remain for a short time, and were then read ; the water all the time flowing 

 over the tumbler. When the temperature was taken at the source (to arrive at 

 which, we usually entered into a gallery or drift, in the floor of which the 

 springs are secured), we dipped our thermometers into the spring, moved them 

 about from place to place to find the hottest part, and read them whilst immersed. 

 When it was practicable, we plunged the thermometers so low as to bring the 

 summit of the mercurial column on a level with the surface of the water, but we 

 could seldom read them in that position, being obliged to raise them a little to 

 bring them to the level of the eye (the head stooping to the floor of the gallery). 

 Sometimes it occurred that the water was so far below the level of the floor 

 of the gallery that we could not get near the thermometers to read them 

 whilst they were immersed. In such cases we got a wine bottle, placed the 

 thermometers in it, tied a cord round its neck, and lowered it into the water. It 

 filled with the water, and we allowed it to remain some minutes, then hauled it 

 up and read the instruments as quickly as possible. Sometimes we were placed 

 in very inconvenient positions, sprawling upon the floor of the gallery, with the 

 head and limbs awkwardly twisted, encumbered with a candle and a thermo- 

 meter, and exposed to an atmosphere resembling that of a Turkish bath ; but we 

 never left a spring without carefully repeating our observations several times 

 when necessary. I most cordially express my thanks to those gentlemen who so 

 patiently accompanied me into these uncomfortable situations, and whose names 

 I shall have occasion to mention hereafter. We often found it very difficult to 

 record an exact temperature when there was an escape of gas from the waters, or 

 where the water rushed up with force. In these cases, the rippling of the water 

 caused the mercury to oscillate in the tube so rapidly, that it was difficult to 

 read the instrument ; but we always endeavoured to catch the highest point. 



3. Place of Observation. — It is difficult to ascertain the exact spot at which a 

 previous observer has plunged his thermometer. So many alterations have been 

 made of late years at the Pyrenean spas, that I scarcely think it likely that I 

 have in many instances succeeded in observing at the precise place occupied by 

 Principal Forbes in 1835. In most instances, my observations have probably 

 been made nearer the actual origin of the springs, because at most of the spas 

 the waters have been traced, by means of excavations, further into the rocks. At 



