"PREVISION OF RAIN BY THE SPECTROSCOPE." [To THE EDITOR OP
THE " SPECTATOR."] Sra,—My attention has been drawn to some comments of yours on a letter of mine, published in the Times of Wednesday, February 7th, on the subject of " The Prevision of Rain by the Spectroscope." You ask,—Can I get anything like equally good results two or three hours sooner P Unfortunately, the spectro- scope for rainband purposes can only be used by daylight, so that would be impossible. At this time of the year, the rain- band may be seen as early as seven a.m., but, for forecasting, it is better to take observations at about nine a.m. or three p.m. all the year round. Although the spectroscope can only be depended on with any certainty for six or seven hours in some instances, yet there are cases, like the one of persistent high rainband mentioned in my letter, when rain may be predicted for days beforehand.
It is of the very greatest importance for us to know whether an approaching depression will be accompanied by much rain or not, for some are attended by a large rainfall, whilst others have with them a comparatively small amount of precipitation. It is here where the spectroscope would prove to be of the highest value, for no other instrument would fore- tell such characteristics; and the sooner means are taken for its adoption at the stations in connection with our Meteoro- logical Office, the better will be the daily predictions of rain or no rain, which, I must confess, are sometimes rather disap- pointing, although those in regard to wind are very successful.
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