18 



ikke bliver udsat tor pludselige Hyk. Udvidelsen af Ac- 

 cumulatorens Stroppe tjener ogsaa til at angive Størrelsen 

 at' den Kraft, sein gaar paa den. 



\'ed AfVejning i Lund fandtes den Vægt, der svarede 

 til hver Fods Udvidelse af en enkelt Strop. og deretter op- 

 sattes nedenstaaende Tabel, der dog selvfolgelig kun angiver 

 omtrentlige Værdier. En Accumulator med 30 Stroppe 

 brugtes til Bundskrabningerne. 



Ved 20 1 / 2 Fods Længde blev Stroppen sprængt. 



Da Loddeblokken vejer sine 50 Pd., den storste Lod- 

 devægt, som ovenfor anført, var 470 Pd., hvortil kommer 

 Yandhenterens Vægt. ser man. at Aecumulatoren. paa hvil- 

 ken der i dette Tilfælde gik en Kraft af noget over 1 000 

 Pd. for Lodderne kom i Våndet, ikke blev meget ;mstrengt 

 i Forhold til hvad den kunde bære. Under Loddets Syn- 

 ken gaar der ikke stor Kraft paca Aecumulatoren. derimod 

 bevirker Lodlinens lange Overflade en saa betydelig Friktion 

 mod Våndet under Ophalingen fra større Dybder, at Ae- 

 cumulatoren kan steekkes ud 0.'"2 til 0."'3 (en halv til en 

 hel Fod.) 



Kautschukstroppene taaler godt Fugtighed. men an- 

 gribes af fedtagtige Stoffe og lider vel ogsaa ved stadig 

 Udsættelse for Vind og Vejr. Saasnart Lodningen var forbi. 

 blev vistnok Aecumulatoren strax firet ned i Våndet, men 

 det kunde ikke altid undgaaes, naar den var udhalt under 

 Raaen til Brug, at den for en kortere Tid kom i Røgen 

 fra Skorstenen. Den i 1876 brugte Accumulator kunde 

 ikke hruges den følgende Sommer. I 1877 anbragte jeg 

 til Forsog omkring Stropperne en Serk af Sejldug. der 

 blev fastspigret rundt Kanten af overste Træskive. (se Fig. 

 1. Skrabe-Accumulatoren, og Titelbilledet samt Fig. 14) og 

 var af samme Længde som Stroppene i Hvile. Ikke usand- 

 synligt paa Grund af denne Beskyttelse holdt Accumulato- 

 rerne sig saa godt, at de kunde benyttes i 1878, dog i 

 den sidste Tid forstærkede med nogle nye Reserve-Stroppe. 



the vessel is rolling or pitching; hut it is also valuable as 

 indicating roughly the amount of tin- strain, by the greater 

 or less extension of the straps. 



By weighting one of the straps. 1 had found, beton 1 

 the Expedition loft Norway on the first cruise, the amount 

 of strain corresponding to its extension. for every succes- 

 sive foot. The results. which of course cannot bnt represent 

 approximate values, are given in the following Table. An 

 accumulator with 30 straps was used with the dredging-gear. 



Length of Strap. 1 Strap. 15 Straps. 30 Straps. 



I- :. Weight in Pounds. 



At tvventy feet and a half the strap broke. 



The weight of the sounding-block being 50 pounds, and 

 that of our heaviest set of sinkers, as stated above. 470, to 

 which must be added the weight of the water-bottle, the 

 accumulator. which accordingly had to bear a strain of 

 but little more than 1000 pounds before the sinkers reached 

 the water, was not exposed to any severe test, consider- 

 ing the great strength of the straps. During the down- 

 ward passage of the lead. there is very little strain on the 

 accumulator; but when bauling in, the friction of one or 

 two miles of cord in the water is so considerable, that the 

 accumulator will be frequently stretched from half a foot 

 to a foot. 



The india-rubber springs stand wet and moisture well ; 

 they are, however. injuriously affected by grease and all 

 kinds of fatty substances, and probably, too, suffer from 

 continued exposure to wind and weather. Immediately after 

 sounding. the accumulator was lowered into the shrouds; 

 but when triced under . the yard-arm for use, it was not 

 always possible to keep it out of the smoke from the tun- 

 nel. The accumulators provided for the first years cruise, 

 in 1876, had to be rejected on the next. To remedy this 

 drawback. I tried. in 1877. the experiment ot nailing round 

 the rim of the upper disc a protective covering of canvass, 

 of the same length as the unstretched straps (see Fig. 1. 

 Dredge- accumulator. Frontispiece. and Fig. 14). Owing, 

 probably. to this simple expedient, the accumulators kept 

 in so sood a condition as to admit of our using them 



