Measuring Sunshine.

Manawatu Herald, 20 August 1896, Page 3

Measuring Sunshine.

The heliograph, although not of recent invention, is. now coming more generally into use since the importance of registering the hours of daily sunshine becomes more popularly appreciated. A recent publication by Professor Eremser estimates the number of heliographs now is use at about fifty in Great Britain, thirty in Germany, twentyfive in France, eighteen in Austria, sixtaen in Italy, and twelve in Switzerland.

The apparatus is automatic. Sun* shine registers itself through lenses, for as soon as the sun comes out of the clouds sufficiently it wilL burn a paper underneath the lense, leaving a black mark thereon. Since the hours of the day are marked on paper under the lense, leaving a black mark thereon, it will be apparent with approximate exactness how many hours each day the sun really shone.

It is shown tbat there ia more sunshine in the south than in the north and also more in the east of Europe than in the west. Near mountains the frequency of fogs lessens the hours of sunshine. Thus the observatory on Ben Nevis shows less than 1£ hours, almost an hour less than elsewhere in* Scotland. The formation of smoke near great cities and manufacturing centres also lessens the hours of sunshine. The interior of London shows but 2J hours, against an average of 3£ hours in Greenwich, and as to 4} hours, elsewhere in Southern England.