818 THE EXPLORATION OF THE FREE AIR. 



enables the kite to be easily flown. In 1891 Mr. Eddy attached a mini- 

 mum thermometer to several of these tailless kites flown tandem, and 

 proposed to obtain in this way data for forecasting the weather.^ In 

 the Proceedings of the Aeronautical Conference held in connection 

 with the Chicago Exposition of 1893 Prof. M. W. Harrington, then 

 Chief of the United States Weather Bureau, quoted Mr. Eddy's esti- 

 mate of the cost of exploring the air to a height of 15,000 feet by 

 means of kites flown in a series. Up to this time it does not appear 

 that self-recording instruments — that is to say, those which make con- 

 tinuous graphic records — hail been raised by kites. In the days of the 

 early experimenters such instruments were too heavy to be lilted by 

 more or less. unmanageable kites. Within the past few years the self- 

 recording instruments made in Paris by MM. Eichard are both light 

 and simple, so that it became possible to obtain simultaneous records 

 at the kite and at a station on the ground from which to study the 

 changes of temperature and humidity. This seems to have been done 

 first at Blue Hill Observatory by my assistants, Messrs. Clayton and 

 Fergussou. In August, 1894, Mr, Eddy brought his kites to Blue Hill 

 and with them lifted a Eichard thermograph, which had been partly 

 reconstructed of aluminum by Mr. Fergusson so that it weighed but 

 2| pounds, to the height of 1,500 feet, where the earliest automatic 

 record of temperature was obtained by a kite.^ During the next sum- 

 mer Mr. Eddy assisted again in the experiments at Blue Hill and 

 secured photographs from a camera carried between his kites. Now 

 that the possibility of lifting self recording meteorological instruments 

 to considerable heights had been demonstrated, an investigation of the 

 thermal and hygrometric conditions of the free air was undertaken by 

 the staff of the Blue Hill Observatory, who had already made a detailed 

 study of the movements of the air at great heights from the observa- 

 tions of clouds.^ 



The development of the kite and its accessory apparatus, and the 

 acquisition of the knowledge how to use them, required much time and 

 resulted in the damage or loss of many kites. Two costly meteoro- 

 graphs, as the combination of self-recording instruments is called, were 

 dropped from a great height and no trace of them could be found. 

 Usually, however, when by the breaking of the line kites and instru- 

 ments were carried away, they fell gently to the ground and were 

 recovered uninjured. It would be tedious to recount the vicissitudes 

 of kiteflying at Blue Hill which have resulted in the present system of 

 work, so only a brief historical statement will be given, to be followed 

 by a description of the methods now in use. At first the Eddy, or 

 Malay kite, as it is sometimes called, was employed. Several of 

 these kites, which were covered first with paper and later with var- 



' Am. Met. Journal, Vol. VIII, pages 122-12.5. 



2 Scientific American, September 15, 1894. 



^Annals Astr. Obs. Harv. Col., Vol. XXX, Part III. 



