November 2, 1900.] 



SCIENCE. 



689 



move en masse and In the direction of common 

 pull exercised by the wind-driven masses of ice. 

 By reason of friction the motion will be com- 

 municated to lower layers of the sea. This 

 cause of surface currents is of importance to 

 the theory of movement of those polar waters 

 which, for several months after the winter ice 

 begins to break up, are free from larger wind- 

 waves. Deprived of its chief sails, the Labra- 

 dor current, always sensitive to wind conditions 

 and at times subject to temporary reversal with 

 contrary winds, yet preserves and perhaps ex- 

 ceeds, during the period of ice-drift, the average 

 velocity of current-flow for the year. 



NOMENCLATURE OF TERMS USED IN ICE NAVI- 

 GATION. 



A USEFUL ' list of some of the terms used in 

 ice navigation by whalers, sealers and others ' 

 has been prepared by Commander William 

 Wakeham, of the Canadian Marine and Fish- 

 eries (Report of the Expedition to Hudson Bay 

 and Cumberland Gulf in the steamship Diana, 

 1897, Ottawa, 1898). Among the terms, the 

 following are here noted with their definitions 

 as expressed by Commander Wakeham : 



Floe — A large mass of floating ice. 



Pan — A small floe or small piece ; one that can he 

 forced aside or slewed. 



A field — A large body of ice that may he seen 

 aronnd. 



Land floe — Ice frozen ast to the shore. 



Collar ice — Is the margin of ice frozen fast to an 

 island or shore, presenting an abrupt wall against 

 which the floating ice rises and falls with the tide. 



Growler — Is a more or less washed and rounded 

 Inmp of ice which rolls about in the water, formed 

 from broken up bergs or detached pieces of heavy 

 old Arctic floe ice. [So called from the sound of 

 heavy churning as the swell breaks at the undercut 

 portion of the pan.] 



Packed ice — Are small pieces closed together and 

 held by the pressure^of ice and currents. 



Batture — Eafted ice [described on page 12 of the 

 report] . 



Pressure ridge — Is the ridge or wall thrown up 

 while the ice has rafted. 



Slack ice — Is detached, so that it may be worked 

 through. Ice is said to be slacking when it begins to 

 be open so as to be navigable. 



Running abroad — Ice is said to be running abroad 



when it opens out or slacks away so as to be navi- 

 gable. 



A nip — Ice is said to be nipping when it begins to 

 close by reason of the action of winds or currents, so 

 as to prevent the passage of a vessel. 



Calving — Ice is calving when the small pieces 

 break off from the bottom and rise to the surface of 

 the water. 



Slob — Is snow afloat and forming into ice. 



Sish — Is thin young new ice, just formed in thin 

 sheets. 



Lolly — Is loose new ice. 



Porridge ice — Is small, finely ground up ice. 



Eatting — Occurs when two pans meet by force 

 either by the action of wind or currents ; the edges 

 are broken off and either rise on top of or pass under 

 the body of the pans. 



A lead — Is a strip of navigable water opening into 

 the pack. 



Slatches — Are considerable pools of open water in 

 the ice. 



Swatch — Is a small pool of open water in the ice. 



Wash — Is the sound of the sea breaking against 

 ice. 



Rote — Newfoundland term for wash. 



Water sky — Is a dark or bluish appearance of the 

 sky indicating open water beyond the pack. 



Reginald A. Daly. 



Harvard University. 



AMERICAN ELECTRICIANS IN LONDON. 



The Central London Railway, the ' Electric 

 Underground,' of London,^ the 'two-penny 

 tube,' is one of the most important and, in 

 some respects, far the most remarkable ex- 

 ample of the work of the American electrician 

 and engineer in Europe, perhaps in the world. 

 It is a subterranean road running from Shep- 

 ard's Bush, at the west, to the Bank in the city. 

 It was opened last June by the Prince of Wales, 

 Its 5| miles of route have seen the expendi- 

 ture of about $15,500,000 during the four years 

 of construction, and many minor bits of work 

 remain to be performed. The original engineer 

 of the work was the late Mr. T. H. Great- 

 head. It was found necessary to come to the 

 United States to secure its exceptionally large 

 and powerful machinery and motive power. It 

 is, in fact, an American electric railway in 

 operation in London, the center of the brains 

 and business of Great Britain. In one respect 

 at least, however, it is novel as to its roadbed : 



