606 KANSAS CITY REVIEW OF SCIENCE. ; 
nent record of the exact size and shape of every sunspot is obtained; these, when 
compared with electrical and other meteorological conditions, will help to settle 
the question whether and in what way the sunspots affect the weather. To such 
a perfection has the manufacture of gclatina-bromide of silver attained, that M. 
Jansen, of Paris, photographs the. Sun in less than one two-thousandth of a 
second. Again, the solar corona, as to the nature of which such varied specula- 
tions have been rife, is only visible during the very few minutes that a total 
eclipse of the Sun lasts, and the observations that can be made in so short a time 
are necessarily very imperfect. Recently, however. Dr. Huggins has succeeded 
in photographing the corona without the intervention of an eclipse. The corona 
is especially rich in violet rays ; now, the eye is less sensitive to small variations 
in the violet rays than it is to the other colors of the spectrum, whereas the violet 
is just what photography deals with most effectively. By cutting off the other 
rays. Dr. Huggins has succeeded in photographing the corona by means of its 
own violet light, and that, too, at a time when hitherto observations have been 
impossible. When his method is perfected, astronomers will be able, with the 
help of the camera, to study the corona and solar protuberances at their leisure. 
The recent transit of Venus afforded a fine opportunity for calculating 
the distance of the Sun, and it is expected that, with the assistance of the hun- 
dreds of photographs obtained, the distance of the Sun from the earth will be 
calculated to within 300,000 miles. The numerous comets, too, have not been 
allowed to pass without leaving their images behind, which show their shapes and 
positions far more perfectly than has hitherto been possible. But perhaps the 
most remarkable achievements are the photographs of spectra of stars and nebulae. 
Not long ago it was hardly possible to photograph stars of the fourth or fifth mag- 
nitude, and even the brighter nebulae shone with far too faint light to enable 
photographs to be taken. But, recently, not only have the fainter nebulae and 
stars, as low as those of the fourteenth magnitude, which are only visible through 
most powerful telescopes, been photographed, but their light, even when dis- 
persed by the prism, has still been strong enough to leave its impress on the 
sensitive plate. Dr. Huggins and Professor H. Draper have each succeeded in 
photographing spectra of nebulae and stars of the twelfth magnitude, and thus 
determining some of the elements contained in worlds so distant from us that 
their light, travelling 186,000 miles per second, has taken thousands of years to 
reach us. Such photographs are especially useful, because they show the faint- 
est lines in the spectra which have hitherto escaped the most practised eye. 
Hardly less remarkable are some of the discoveries of Captain Abney, the 
prince of photographers, in his experiments on the infra-red of the spectrum ; he 
has recently shown that between the earth and the Sun, and quite outside our 
atmosphere, there exist accumulations of benzine and alcoholic derivatives. 
Alcohol in temperance drinks, alcohol in rainwater, alcohol in space, alcoh 1 
everywhere. 
Again, in meteorology the art of photography will prove to be of immense 
use. A regular system of photographing the clouds by means of a specially 
