PRESIDENT'S ADDRESS. Ixxiii. 



the earth, and no doubt in course of time forecasting will 

 improve ; but at present the influences which determine 

 the weather seem very complicated and difficult to grasp. 

 Observations of clouds at Epsom, continued for eight years 

 at hourly intervals, shew that the commonest form of cloud 

 is cumulus, which occurred on 1622 days, stratus coming next 

 with 1155, as well as many other facts connected with clouds. 

 It has been suggested that the presence of volcanic dust in 

 the atmosphere is responsible for a diminution of the amount 

 of the sun's heat reaching the earth, which seems to be borne 

 out by the agreement in the past 150 years between eruptions 

 and cold periods. A valuable contribution has been made 

 to our knowledge of the Aurora by a series of simultaneous 

 photographs of Aurorae at two stations about 17 miles apart, 

 which will afford data for working out details as to their 

 form, position, and altitude. The rate of movement of 

 Greenland glaciers has been found to be from one to two 

 metres per day. Both these and glaciers in Norway and 

 North America seem to be retreating in position, as are 

 many of those in the Alps, whilst most of those in the Pyrenees 

 are advancing. The Grand Pacific Glacier in N. America has 

 gone back the great distance of 25 kilometres in 33 years. 

 Experiments continue to be made with regard to detecting 

 the neighbourhood of icebergs, the most reliable method 

 being the observation of the fall of air-temperature caused by 

 them even when at a considerable distance. They rarely give 

 an echo, and the temperature of the water near them is 

 uncertain. A Government grant will probably be made this 

 year for the purpose of research into this matter. An interesting 

 book by our former V.-P., Dr. Vaughan Cornish, on Waves of 

 Sand and Snow, has lately been published. We have to thank 

 him for several valuable papers on this and kindred subjects, in 

 our past volumes. 



ELECTRICITY. 



At the Berlin Meeting of the International Electrotechnical 

 Commission, at which no less than 24 nations were 



