16 DEPAETMENTAL REPORTS. 



The hot-wire receiver, or boloscope, was found to be the most sensi- 

 tive of any j'et used in the experiments. Its action was positive, and 

 during the early spring it gave excellent results; messages were 

 transmitted with a rapidity almost equal to that of the ordinary tele- 

 graph. Quite satisfactory tests were made before a board from the 

 Army and one from the Navy. It was thought that the Bureau had 

 finally devised a receiver that would take the place of all others in 

 use; but as the season advanced into summer and unstable atmos- 

 plieric electrical conditions became more frequent it was found that 

 the minute platinum loops on which the active principle of the bolo- 

 scope depended would frequently burn out after connection was made 

 with a A'ertical wii*e. 



It has so far been found impossible to send messages any appreciable 

 distance over land or fresh water, or to attune the transmitter to the 

 receiver so as to overcome the difficulties of interference should a 

 second transmitter generate electric waves within the same field. 



I am of the opinion that the use of wireless telegraphy in its present 

 state is limited to the transmission of messages between moving ships 

 and between ships and the land, and that wherever permanent com- 

 munication is required the cable or the land wire is the more reliable 

 means of communication and probably the more economical. 



Our experiments during the past year were conducted over a course 

 bet\^''een Manteo and Cape Hatteras, a distance of about 50 miles. 



INSTRUMENTS. 



STATION EQUIPMENTS. 



Nearly all stations are now fully equipped with automatic instru- 

 ments recording wind velocitj^ and direction, the temperature and 

 pressure of the air, and the duration of sunshine and rainfall. The 

 extensive and thorough inspection of stations that has been made 

 within the last two years has resulted in numerous recommendations 

 by the inspectors, which, in the main, have been carried out and which 

 have necessitated the replacing of old automatic apparatus with that 

 of the most approved type. We have been obliged to postpone the 

 equijjment of some stations already listed to be supplied, but it is 

 exi^ected that these will receive attention during the next few months. 



It is considered, in the present connection, that a station is fully 

 equipped with automatic instruments whenever records of the follow- 

 ing meteorological conditions are continuously and automatically pro- 

 duced, namely: Wind velocity, wind direction, temperature, pressure, 

 rainfall, duration of sunshine. 



On June 30, 1902, there were in operation IDl stations at which at 

 least one meteorological element was automatically recorded, and in 

 order to set forth graphically the present status of the equipment of 

 stations, these may be separated into the following classes: 



(a) Stations completely equipped as defined above _ _ 124 



(b) Stations awaiting equipment as supplies become available 24 



(c) Stations maintained by agents where the equipment is necessarily simple 



and hence incomxilete ...' 9 



(d) Special display or other stations, at which records of some particular ele- 



ment, generally wnnd velocity only, is desired 17 



((') Regular stations now partly equipped, but which are of sraall importance, 

 or so circumstanced that further additions to the present eqtiipment 

 are not considered desirable or necessary 17 



Total 191 



(/) New stations announced but not yet established. 



