88 



SCIENCE. 



[Vol. IV., No. 77. 



with great ease the difference of potential be- 

 tween the poles of a single cell, on the other, 

 it is readily seen that static electricity acquires 

 its predominant but not exclusive character 

 from great difference of potential, while gal- 

 vanic electrichYy produces its most striking 

 effects by the transfer of great quantities of 

 electrichVy as a current. The terms ' static ' 

 and ' galvanic ' serve only to denote the ex- 

 tremes of electrical phenomena. In fact, the 

 contact theory of potential difference unifies the 

 whole science by giving a common account of 

 the historically diverse forms of static and gal- 

 vanic electricity ; for it is now generally be- 

 lieved that the potential difference in frictional 

 machines is clue to contact of dissimilar bodies, 

 while the old contest which began with Volta 

 and Gralvani is now set at rest by the happy 

 compromise of assigning electromotive force 

 to contact, and the energ} 7 of the current to 

 chemical action. 



The first volume of Professor Wiedemann's 

 new work treats of general electrical phenom- 

 ena, the excitation of electricity by contact of 

 dissimilar bodies, Ohm's law and its conse- 

 quences, determination of resistance in a great 

 variety of bodies, measurement of electromo- 

 tive force, and galvanic elements. The second 

 volume is devoted to dielectrics, the theory of 

 frictional and influence machines, the relations 

 between heat and electricity, and to electro- 

 chemistiy. 



Mathematical treatment of the subject is in- 

 troduced so far as it serves to establish general 

 principles or theories, and to discuss methods 

 and confirm results. Beyond this, mathemati- 

 cal discussions, which are interesting as mathe- 

 matical exercises, but which do not advance 

 our knowledge of physical principles, are 

 either omitted entirely, or are referred to by 

 citation. 



The applications of electricity are noticed 

 only so far as they serve to give complete- 

 ness to a scientific knowledge of the subject. 



It was reported a 3'ear ago that the manu- 

 script of the two concluding volumes was nearly 

 ready for the press. 



Professor Wiedemann has placed all physi- 

 cists under obligations by his full and logical 

 presentation of all the facts and principles of 

 the science of electricity. While the work does 

 not possess the originality of Maxwell's, and 

 is written with an entirely different purpose, 

 it must, nevertheless, be classed with it as one 

 of the great works on electricity. Considered 

 from the point of view of giving a complete ac- 

 count of what is known respecting this branch 

 of physics, and of showing what each investi- 



gator has contributed to our common stock 

 of knowledge of electricity, this book is not 

 equalled by any other in any language. 



H. S. C. 



NOTES AND NEWS. 



No piece of news of wider interest has traversed 

 the wires of two continents since Science was founded 

 than that which announced last week the rescue of 

 the Greely party. The story of their frightful suf- 

 ferings, their sad losses, and the successful accom- 

 plishment of their duties, is briefly told in the two 

 despatches from Lieut. Greely, which we print in full 

 below. It appears, that, when found, they were hud- 

 dled in a tent, which the force of the gale had blown 

 down upon them. The strongest of them could hold 

 aloft the signal-flag, to guide the relief-party they 

 could hear but not see, for two brief minutes only; 

 and the weakest begged to be left to die in peace. 

 Their provisions were utterly exhausted, and they 

 had been living for weeks on a stew made from their 

 sealskin clothing, with lichens and small shrimps; 

 and it is highly probable that a detention of the relief- 

 party for two days would have cost the entire party 

 their lives. 



The following two despatches from Lieut. Greely 

 were received by the chief signal-officer on July 17: — 



Brainard, Bierderbick, Connell, Fredericks, Long, 

 and myself, the sole survivors, arrived to-day, having 

 been rescued at the point of death from starvation 

 by relief-ships Thetis and Bear, June 22, at Camp 

 Clay, north-west of Cape Sabine. All are now in 

 good health, but weak. Sergeant Ellison, who was 

 rescued, died July 8. Cross died last January; 

 Christianson, Linn, Rice, Lockwood, Jewell, and 

 Edwards, in April; Ellis, Rainston,Whisler, Israel, in 

 May; Kingsbury, Salor, Henry, Bender, Pavy, Gar- 

 diner, Schneider, in June. Abandoned Fort Conger 

 Aug. 9. Frozen in pack, off Victoria Head, Aug. 29. 

 Abandoned steam-launch, Sept. 11, eleven miles 

 north-east of Cocked Hat Island. When on the point 

 of landing, we were three times driven by south-west 

 storms into Nares Sea. Finally landed, Sept. 29, in 

 Baird Inlet. Learning by scouting-parties of the 

 Proteus disaster, and that no provisions had been left 

 for us from Cape Isabella to Sabine, moved, and estab- 

 lished winter quarters at Camp Clay, halfway be- 

 tween Sabine and Cocked Hat. An inventory showed, 

 that by a daily ration of four and one-third ounces 

 of meat, seven of bread and dog-biscuit, and four 

 ounces miscellaneous, the party would have ten days' 

 full rations left for crossing Smith Sound to Littleton 

 Island, March 1. Unfortunately, Smith Sound re- 

 mained open the entire winter, rendering crossing 

 impossible. Game failed, despite daily hunting, from 

 early in February. Before the sun returned, only 

 five hundred pounds of meats were obtained. This 

 year minute shrimps, seaweed, sassafras, rock- lichens, 

 and sealskin were resorted to for food, with results 

 as shown by the number of survivors. Last regular 

 food issued May 14. Only a hundred and fifty pounds 



