56 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



During a shower he finds the following law to hold good 

 universally: At the place of the shower there is a strong de- 

 velopment of positive electricity ; round this there is a zone 

 of negative, and beyond this again, positive. The nature of 

 the electricity observed depends upon the position of the ob- 

 server with respect to the shower, and the phenomenon will 

 change according to the direction in which the shower is 

 moving. Sometimes negative electricity may be observed 

 during a shower, but this is always due to a more powerful 

 shower farther off. These conclusions have been supported 

 by means of telegraphic communication with neighboring 

 districts. It appears, then, that, except when the moisture 

 of the air is being condensed, there is no unusual develop- 

 ment of electricity. 12 A, June 20, 1872, 147. 



VOLCANIC SAND IN CHILE. 



The Hevista del JSur, of Chile, states that showers of sand 

 occurred on the 3d of July, in Araucania, of sufficient extent 

 to cover up all the planted fields of the Indians, and oblige 

 them to take refuge on the north side of the mountain. This 

 rain, supposed to have come from an eruption of Mount Llai- 

 ma, distressed the Indians so much as to drive them into the 

 neighborhood of the white settlements. Panama Star and 

 Herald, September 23, 1872, 2. 



STEEL SOUNDING-LINES. 



Sir William Thomson, in a communication read before the 

 British Association, recommends the use of steel wire in 

 deep-sea soundings. The great difficulty in such operations 

 consists in the resistance of the water to the line, which is 

 usually overcome in very deep soundings by employing ex- 

 tremely heavy weights. Beyond a depth of 300 fathoms the 

 ordinary lead ceases to be available, and until very recently 

 the difficulty of bringing up a long line and heavy weight 

 from a considerable depth was so great that it had become 

 the practice to leave the weight behind, simply bringing up 

 a sample of the bottom. Farthermore, when there is great 

 resistance to the line, the currents sometimes carry it away 

 to a considerable distance, so that it is difficult to know when 

 the bottom is actually reached. In view of these facts he 

 has lately been experimenting in mid-ocean, at a depth of 



