those who were affected. This shows that it is only in the blood and tissues of persons who are more or less delicate that the microbes of the atmosphere find a soil suited to their development, and that on persons in tolerably perfect health they have no effect at all.

For more ample details on this important subject, I must refer to my History of Bacteria, which appeared in the early numbers of my medical journal.1 The cause of disease must be looked for beyond bacteria.

1 Phipson, "A History of Bacteria," and "Supplements to a History of Bacteria," in Journ. of Med., etc., London, 1880-1894. See also my Health Notes and Curiosities of Medical Science, London, Routledge, 1898, one vol.

CHAPTER XXII.

State of the Atmosphere in any given Locality--Immediate Weather--Table for British Isles and Northern Europe generally-Rainfall.

FROM a practical point of view, the instruments which are the most useful in supplying data regarding the state of the atmosphere in any given locality are the barometer and thermometer.

Before the present system of telegraphing the weather to be expected in any particular quarter was put into practice, it was quite possible, by a careful observation of these two instruments, to foretell by about twentyfour hours what kind of weather was coming. But such observations were rarely made; few seaports were properly provided with these instruments, and their indications were nowhere precisely understood.

I have already mentioned several important indications supplied by the barometer and thermometer; and I will now add a few practical details as regards the immediate weather of any given locality-that is, the weather that may be expected in the next twenty-four hours as it can be foreseen by scrutinizing the movements of the mercury in the barometer, the direction of

K

the wind at the time of observation, and the aspect presented by the sky.

Fitz-Roy has laid down the rules for the barometer in a very clear manner.1 It rises in our north latitudes for cold, northerly (N., N.E., N.W.) winds, less wind, and dry air; and it falls for warm, southerly (S., S.E., S.W.) winds, for more wind, and wet, the only exception apparently being, occasionally, with wet from the northeast (when it remains high). In the Southern hemisphere the words "south, southerly," etc. must be substituted for "north, northerly," etc.

The barometer expresses the connection of the present wind with that which is about to blow; and this alone is sufficient to render its indications of very great service to us.

Such being the case, I will give here a little table, the indications of which are the results of long experience, feeling certain that it will prove extremely useful.

The first thing to be done is to ascertain the direction of the wind by observation of the weathercock, or, better still, by the direction of the lower clouds. Then, we must observe with care the state of the barometer and the thermometer. It will be best to make these observations always at the same hour, say between nine and ten in the morning, regularly.

Here is the little table in question: it applies to the British Isles, Belgium, Germany, France, and northern Europe generally.

1 Fitz-Roy, The Weather Book, second edition, p. 10.