SUPPLEMENTARY REPORT ON METEOROLOGY. 153 
4. Meteorological extremes have always a certain interest 
which makes them worthy of preservation, whether they be 
if practicable, to one-tenth, If possible one person should note the results at 
the instant that the other observes, and to avoid errors the observers should 
then change places. ‘The stem of the thermometer should be immersed in the 
water, so that the whole mercurial column may be of the same temperature ; it 
should be kept there until the reading becomes quite stationary, and the read- 
ing made whilst so immersed. 
Hot springs are either uninclosed, or applied to the supply of baths, &c. 
In the former case great care must be taken in marking distinctly the locality, 
as springs often occur so near to one another that confusion readily arises: the 
bearings of any permanent objects near should be given, and the popular name 
of the spring, if it have one. If the spring be collected (as is usually the case) 
from a number of imperceptible sources, the fact should be mentioned and 
the hottest part taken. In the case of the supply of baths, too great care in 
reaching the real sources cannot be enjoined. ‘The servants of the baths are 
often ignorant of the true springs, and are unable or unwilling (because they 
are difficult of access) to point them out. When the real source cannot be 
reached (from being underground or built up) the nearest bath cock should be 
tried, having been first opened for some time, and the observer should record 
the number of the cock, its distance from the spring, and the nature of the con- 
duit, as well as give an eye-sketch of their relative positions. Where the wa- 
ter is stopped in its passage by reservoirs, these should be especially noticed, as 
they render the observation of temperature of little value. Often the spring 
rises over a great extent of surface into a large piscina or public bath. {n this 
case the observation is generally unsatisfactory, but the temperature of different 
points of the basin should be ascertained and the hottest recorded. If gas rises 
it should be ascertained whether its temperature differs from that of the water. 
The traveller should repeat his experiment on different days and at different 
hours, and at as great an interval of time as his stay permits. As many springs 
as possible (of those which are really independent) should be observed, and to 
prevent mistakes as to the independence and purity of the springs (for those 
more esteemed are often mixed with others of inferior quality) the best author- 
ity (usually the resident physician) should at once be consulted. With a view 
to comparison with former observers, changes in the management of the reser- 
voirs, &c., should be inquired for, and their date noticed. 
No ordinary traveller can undertake an analysis of mineral water, but if the 
spring be employed medicinally he may probably obtain some information 
from the resident physician or druggist, which should be preserved (with the 
authority). He may further, after a little experience, judge (by taste and smell) 
to what class of springs it is referible, as sulphureous, alkaline, saline, chaly- 
beate or acidulous. The easier experiments which he might further make 
would relate to the specific gravity of the water, and to the nature of the gas 
evolved, which is a very important question. There are cases in which it might 
be desirable to preserve, well corked, a portion of the water for analysis, but such 
are comparatively rare. 
Historical and other information may often be got from physicians and in- 
telligent proprietors of baths. Such persons might sometimes be induced to 
undertake observations every week or month on the precise variations of 
temperature to which a spring is subject. Almost any thermometer would suf- 
fice for this purpose, as only small variations are wanted, and the absolute error 
might be found by comparison with the traveller’s standard. But in all cases 
the authority for every statement not directly verified: by the traveller himself 
ought to be distinctly given. 
