134 abstracts: physical chemistry, mineralogy 



tion in 1910. Since the publication of the 1905 declination chart so 

 many additional data have been accumulated and the secular change 

 has undergone such material modification that a new chart was needed. 

 January 1, 1910, was chosen for the date of the chart in order that the 

 reduction of the declination data to a common epoch, might be based 

 upon actual observations of the annual change. Special attention was 

 given in 1909 and 1910 to obtaining observational data of the secular 

 change. 



The isogonic lines are shown on the chart for each degree of magnetic 

 declination. The distribution of the lines of equal change shown on the 

 chart differs materially from that of the lines on the 1905 chart (which 

 the present chart now supersedes), the most marked characteristic 

 being a crowding of the lines toward the line of no annual change. West 

 declination is increasing much more rapidly in the North Atlantic states 

 than was supposed in 1905, the annual change now being about six 

 minutes in the New England states. On the Pacific coast east declin- 

 ation is increasing more rapidly than it was in 1905, but apparently the 

 region of maximum annual change is now some distance inland. 



Under the present conditions of rapidly varying annual change it is 

 not possible to predict accurately what these changes will be even for a 

 few years in advance. 



In connection with the present large annual change in New England 

 it may be noted that west declination is ir creasing about seven minutes 

 a year in Bermuda and about nine minutes per year at Vieques Island, 

 Porto Rico. R. L. F. 



PHYSICAL CHEMISTRY.— Die Untersuchung von Silikaten. Arthur 

 L. Day. Z. Elektrochem., 17: 609. 1911. 

 An address given at the annual convocation of the Bunsen Gesell- 

 schaft, held at Kiel, Germany, reviewing some of the more interesting 

 phases in the laboratory investigation of silicates compared with some 

 of the more familiar fields of physico-chemical research. 



MINERALOGY. — The melting points of minerals in the light of recent 



investigations on the gas thermometer. Arthur L. Day and Robert 



B. Sosman, Geophysical Laboratory. American Journal of Science 



(4) 31: 341. 1911. 



Before the completion of the gas thermometer measurements to 1550° 



C. at the Geophysical Laboratory, the temperature measurements made 



in this laboratory with thermo-elements had been interpreted in the 



