recording meteorological instruments used in this manner. Mr. Eddy, of New Jersey, used his kites in making this first trial. The work has been pushed with such success that records of atmospheric pressure, temperature, relative humidity and wind velocity have been secured by means of kites up to a height of 15,800 feet above the sea.
In a pioneer work of this kind, it was found necessary not only to modify old apparatus and methods so as to fit the novel applications, but also to devise new ones as well; and many of the details of the system as established at Blue Hill have been copied by meteorologists in the prosecution of similar researches both in this country and in Europe.
In this connection the Blue Hill studies of the clouds have led to the consideration of many problems to which these phenomena either directly or indirectly furnish a key. As in other studies carried on there, this work has been undertaken in the light of what has been done by other investigators; and in Mr. Clayton's report on the subject an excellent summary of what has already been accomplished introduces us to the more distinctively Blue Hill work. It has too frequently happened
that the cloud work which has been done in different parts of the world has had its value much decreased owing to uncertainties in cloud nomenclature, and much of the recognized value of the Blue Hill work is to be attributed to the great care exercised in this preliminary matter. A valuable contribution has been made to the revision of cloud nomenclature, taking into account the elevations of the clouds. The annual and diurnal periodicity of clouds has been carefully studied on the basis of cloudiness at different levels.
