MECHANICAL PROPERTIES OF THE PROPOSED ATLANTIC CABLE. 411 



elasticity, &c. The wires were of three sorts, namely, steel and iron in its 

 homogeneous or simple state of manufacture from coke, coal, and cliarcoal. 

 From the samples the following results were obtained : — 



Experiments to determine the Strength and other properties of Steel, Homo- 

 geneous, and Iron Wire, calculated to establish a secure and, as nearly as 

 possible, a jjerfect Cable for an Electric Telegraph across the Atlantic. 



Summary of Results of Experiments on Bare Wires. 



Number of 

 Exp. in 

 Table of 



completfd 

 Cable. 



Name of manufacturer. 



Dia- 

 meters 

 of wire, 



in 

 inches. 



Description of wire. 



Breaking- 

 weight of 

 wire, in 

 lbs. 



Ultimate 



elongation 



in .50 



inches, 



in inches. 



I & 2 



4& 5 

 6 & 7 

 8 &9 



10 & II 

 12 & 13 



14 

 16 

 17 & 18 

 20 

 21 

 22 

 23 

 24 

 32 



33 

 I 

 2 





3 

 4 



Is 



Messrs. Taylor & Co 



„ Ilorsfa Is 



,, Horsfalls 



„ Johnsons 



,, Johnsons 



,, Shortridge & Co. ... 



,, Smith and Houghton 



„ Hughes 



„ Firth and Sons 



„ Jenkins and Hill ... 



„ Jenkins and Hill ... 



„ Eyland Brothers ... 



,, Taylor & Co 



„ Taylor & Co 



„ Horsfall, No. 7 



,, Horsfall, No. 9 



„ Johnson, 1 



„ Johnson, 2 



Johnson, i A 



„ Johnson, 2 A 



,, Johnson, 3 A 



•087 

 095 

 •097 

 •093 

 •098 

 •089 

 •091 

 •091 

 •088 

 •085 

 •085 

 •093 

 •089 

 •095 



•095 

 •095 

 •09s 

 •095 

 •095 



HiBmatite 



Homogeneous ... 

 Special homogeneous 



Charcoal 



Galvanised 



Homogeneous 



Homogeneous 



Charcoal 



Homogeneous 



Soft patent steel ... 



Annealed steel 



Charcoal 



H.^matite, S3 



Hiematite, S 4 



Homogeneous, No. 7 

 Homogeneous, No. 9 



Steel wire 



Patent steel 



Horn ogeneoiis 



Hom ogeneous 



Special charcoal . . . 



650 



950 



850 



750 



650 



650 



1250 



600 



650 



6co 



450 



55° 



550 



75° 



1 150 



1050 



1950 



1950 



950 



550 

 750 



•280 (a) 

 •366 (//) 

 •267 (c) 

 •173 

 •198 (t^) 

 •190 (e) 

 •712 

 •198 

 •2.8(/) 

 •264 (g) 

 2760 (A) 

 ■320 

 •171 (?:) 

 •366O') 

 •480 

 •550 



•853 

 •63 I 

 •346 

 •116 

 •170 



(a) -087 inches at the fracture. 

 (*) '083 „ „ 



(o) -092 „ „ 



{d) -098 „ „ 



(«) 088 



(/) -086 inches at the fracture. 



Iff) '083 



(A) '071 >. .. 



(«•) -082 „ „ 



U) '082 „ „ 



From the above, it will be seen that, out of 21 specimens experimented 

 upon, the maximum of strength rests with Johnson, and the minimum 

 with Jenkins, HOI & Co., the ratios being as 1950 : 450, or as 4-33 : 1. The 

 maximum of elongation to that of the minimum varies with a load of 550 

 lbs. as the numbers -320 for Eyland's and about -014 for Johnson's steel wu-e 

 in experiment 2, being in the ratio of -320 : -014, or as 22-8 : 1, nearly. 

 Softness and ductility have always been considered an important element in 

 the construction ; but this measure of ductility is probably overrated, as the 

 Ryland wire, with the last weight laid on (50 lbs.), was sufficient to extend 

 or stretch considerably before it broke. Viewing the subject in this light, 

 it is obvious that a very high ductility with a low standard of strength is 

 not what is wanted, but a combination of strength and ductility that will 

 jjrevent snapping from brittleness, on the one hand, and give the reqtiisite 

 powers of elongation without material injury to the strength, on the other. 

 What is therefore wanted in these wires is tenacity united to ductility in 

 resistance to a tensile strain, without incurring fracture, up to at least seven- 



eighths of its ultimate strength. 



2e2 



