362 



Transactions. — Chemistry and Physics. 



for specific gravity of water by Volkmann's table, and for air 

 by Kegnault's figure, and for dilatation at 0000063 per degree. 

 The specimens were about 35 mils diameter, varying about 

 02 mil from the mean at most as tested by a micrometer, 

 the diameter being obtained from the lengths and weight, and 

 the lengths about 5 ft. or 6 ft. The wires generally stretched 

 about one-thousandth after coiling round a 3 in. drum. The 

 mean length was taken. Without going into detail, I may 

 say that I believe each measurement to have been accurate to 

 1 in 1,000, which is quite sufficient for the purpose. 



Table of Specific Resistance of Tin Wires Hard-drawn. 



Description of Material. 



« So 



x 







II. 



III. 



Specific 



Resistance, 



Microhms 



per C.C. 



0° C. I 15° C. 



IV. 



a ® . 



o g « 



° 12 



Q> ^ ^i 



3° M 



VI. 



Diameter 



by Micrometer, 



with Variation 



from Mean. 



Fuse-wire (sample A) — 

 No. 1 



No. 2 

 No. 3 

 Fuse-wire (sample B) 



Ditto, purified by oxi- 

 dation and reduc- 

 tion 



Fuse-wire (sample C) 



Purchased as " cbemi- 

 cally pure " (Merck) 

 Australian tin 



Ditto, remelted in air 



Plumbers' "block" .. 



Cornish tin 



Fine fuse-wires drawn 

 by the maker (nomi- 

 nal diameter) — 



(No. 2 .. 

 14 ' (No. 1 



113 .. 



9 6 .. 



No. 1 

 No. 2 



Ineot. 

 7-2880 



7-2790 

 7-2863 

 7-3000 



7-2812 



7-3144 

 7-2935 

 7-2833 

 7-2914 



7-3088 

 7-3606 



o 



CO 



r <o ~\ 



■yj 



10-969 



10-951 

 10928 

 11-263 



11-088 



11-233 

 10592 

 10-944 

 10 835 

 11-082 

 11-219 



10598 

 10-547 



11-672 



11-653 

 11-628 

 11-984 



11-798 



11-953 

 11-269 

 11645 

 11-529 

 11-791 

 11-939 



11-277 

 11-222 



10368 11 032 



10116^0764 

 10-118 10-767 



10-030 



10-690 



224-6 

 224-2 



(223-5 \ 

 12230/ 



(221-3) 

 221-01 

 J 224-9 | 

 1224-3/ 

 I 224 6 I 

 \ 224-2 f 



1219-6) 

 I 219 3/ 



j 225-6 1 

 (225-0/ 



30-638 



36-965 



36-80 



796 



2048 



+ 0-27 

 -0-13 

 +0-2 

 2 



n 



35 25 

 35 circ 

 35 circ. 



30-556 J + jj J 



36 88 

 36875 



35 585 



35-7 



36-71 



35-68 



14-68 



11-27 



957 



801 



+0 43 

 -0-12 

 + 0-13 

 -0-07 

 i +0-08 

 1 -0-12 

 + 005 

 -01 

 +0-19 

 -0-21 

 + 002 

 -005 



(+0-07 

 1 - 003 



+ 05 



-0-1 

 j +0 08 

 | -0-12 

 j +0-015 

 1-0-01 



