INDUSTRIAL PROGRESS DURING THE YEAR 1876. xliii 



with instructions emanating from the Observatory at Stonyhurst, in 

 England. They were continued for about five months at intervals 

 of every two hours, and will afford valuable data relating to terres- 

 trial magnetism. 



The Bureau of Longitudes at Paris has published a map of mag- 

 netic variations for France, for 1876, prepared by Marie Davy, which 

 will hereafter be issued annually in connection with the Annuaire 

 of the bureau. 



Lieutenant Weyprecht presents a synopsis of the results of the 

 magnetic observations made by the Austrian Polar Expedition un- 

 der his command in 1872-1873, in which he states that declination, 

 inclination, and total intensity are greater in the regions traversed 

 by himself than as given by General Sabine for 1840-1845, and than 

 those computed by Erman and Petersen for 1829, according to Gauss' 

 formula. His observations of daily variation are the only ones as 

 yet published from arctic regions, except those made at Lake Atha- 

 baska and Fort Simpson. From them it seems to result that the 

 total intensity sulfered little or no variation in consequence of the 

 magnetic perturbations, which latter affected only the declination 

 and inclination. 



VULCANOLOGY. 



Of recent publications in reference to earthquakes, we should men- 

 tion the two important volumes by Schmidt, at Athens, one of which, 

 " Studies on Earthquakes," affords the best collection extant of sta- 

 tistics of this phenomenon and its relation to the moon, the baromet- 

 ric pressure, etc. The second volume, " Studies upon Volcanoes," is 

 especially devoted to Santorin, Vesuvius, Bale, Stromboli, and Etna. 

 In his observations upon these volcanoes, Schmidt has combined the 

 accuracy of an astronomer's studies with the caution of the true in- 

 vestigator. 



Serpieri has subjected to a detailed study the observations of earth- 

 quakes that have been made in Italy by means of delicate pendulum 

 seismometers. According to Alexis Perry, Serpieri's memoir is one 

 of the most important that has lately appeared on this subject. 



Pictet has communicated to the Society of Physical Sciences at 

 Geneva the results of his experiments made in Egypt on the propa- 

 gation of the heat rays of the sun through different substances, espe- 

 cially sand. He had proposed to himself to verify the idea suggested 

 by Sorat, that the sand acted somewhat like a sheet of glass ; that is 

 to say, that it was diathermanous for luminous heat, and atherma- 

 uous for obscure heat. Pictet has found that in the diurnal changes 

 of temperature a much greater accordance takes place between the 

 sand and the glass than other substances, like wood or coal, even 

 when these two latter have been painted the color of sand. 



Mohr shows that the observations of temperature in the artesian 



