changes taking place in the solar surface. The labours of the Observatory in connection with the sun have been so persistent that photographs taken by the large telescope in the dome of the Observatory exist from 1859 to quite recently. Placed on the roofs so that they may catch any ray of sunshine there may be, are two sunshine recorders. One is a bowl of wood, over which is placed a spherical glass three or four inches in diameter; the other is a brass bowl, inside which is a specially prepared piece of blue cardboard. When the sun shines on the first it burns the wood away, and as the bowl remains there for six months, the amount of wood charred shows what "bright Phœbus" has been doing to gladden this earth of ours during that time; the second records his appearance through one day only. When the sun shines it burns a line on the cardboard, and his disappearance for any length of time is notified by the absence of the charred line. The notion here turned to scientific account is precisely that of the smoker whose matches have failed him. If the sun be shining he takes a spectacle glass, and holding it between the sun and his pipe, secures a light.
Cloud photography.
Rapid as has been our glance at the operations of both the Meteorological Office and one of the principal observatories associated with it, we have said enough to show their importance. When one thinks of the accumulation of meteorological minutiæ which is resulting from the preservation of the reports from so many places as to the wind, rain, sunshine, and all the rest of it, one may be tempted to ask whether it is worth the trouble it involves? If the observations are of use to those who want to know the probable state of the weather during the next twenty-four hours, where can be the utility of tabulating them year after year with as much care as is exercised in the registering of births, marriages, and deaths? Well, many an agriculturist would give a satisfactory reply to this question. Suppose he wishes to ascertain the amount of moisture his land is likely to require. The Meteorological Office can inform him precisely as to the average quantity of rain which has fallen in his district for years past. Or, supposing one is particularly anxious to ascertain the climatic character of a place where one is thinking of living, or to which one wishes to send an invalid friend. To learn whether the place is dry or damp, windy or quiet, one has only to go to the Meteorological Office, and the chances are its pigeon-holes will supply the very information wanted. Or, say, a civil engineer is about to build sewers in some new locality. One of the things he has to guard against is making them too small to carry off the rain water which is likely to fall. But how is he to tell whether the normal amount is little or much? He applies to the Meteorological Office, and they can inform him not only how much rain fell on an average every hour of every day in the last twenty years, but exactly how often there had been exceptional downpours, which would make great demands on the drains. The civil engineer thus learns precisely what it is of the utmost importance he should know. Or, to look at the matter from another point of
