Sunshine recorders automatically registering time and duration of insolation are used at meteorological and climatological research centres, observatiories, spas and health resorts, in agriculture, horticulture, viticulture and vegetable gardening. The instruments are set up on flat roofs or on clear ground in such manner as to be well exposed to solar radiation, during the whole day. The type of instrument to be chosen depends on the latitude of the place installation. This recorder consists essentially of a glass sphere mounted concentrially in a section of a spherical metal bowl, the diameter of which is such that the sun stays are focused sharply on a card held in the grooves, in the bowl. Three overlapping pairs of grooves are provided in the bowl to taken up cards suitable for the different seasons of the year.
