412 BELLINGER: HIGH FREQUENCY AMMETERS 



that in general there was a fall in temperature of about 1° in 4 

 or 5 miles in approaching the various bergs. In all but two in- 

 stances the minimum temperature was found near the bergs. So 

 far as our records go, therefore, it does not seem possible to draw 

 positive conclusions as to the absence or proximity of ice from 

 the temperature records of sea water. This is not a condemna- 

 tion of the use of suitable recorders on ships. As Barnes has 

 shown, the temperature record may give valuable information 

 on the approach to shore and shallow water, on the identifica- 

 tion of characteristic ocean currents, and, as his records seem to 

 show, even of the proximity of icebergs in some parts of the 

 ocean where the variations are less erratic than in the regions in 

 which our observations were made. 



If the "characteristic iceberg effect" observed by Barnes, i.e., 

 rise of temperature on approaching icebergs, had been present 

 around the bergs observed by us and of the same or even much 

 less magnitude, our records would have rendered such an effect 

 evident, notwithstanding the irregular variations of temperature 

 usually found to exist. In view of the differences in the charac- 

 ter of the records obtained by Barnes and by us, it is very desir- 

 able that further observations be made in different parts of the 

 ocean, and under as varied conditions as possible, before attempt- 

 ing to draw final conclusions. 



In conclusion, we wish to express our indebtedness to Captain 

 Decker, Captain Hughes, and their officers and crews for their 

 hearty cooperation and many acts of kindness during our stay 

 on shipboard. 



ELECTRICITY. — High-frequency amjiieters. J. H. Bellinger. 

 To appear in the Bulletin of the Bureau of Standards, Sci- 

 entific Paper No. 206. 



For the measurement of current at radiotelegraphic frequen- 

 cies, about 50,000 to 2,000,000 cycles per second, it is general 

 practice to utilize the thermal effect of the current. The elec- 

 trodynamic effect of the current has not been very successfully 

 utilized; because, when the wire is coiled up to form an electro- 



