78 Mr. R. H. M. Bosanquet on the Magnetic 
K. Forged Ring Crown Iron. 
Mean diameter. . d@ =22:°725 centim. 
Bar-thickness . . 2R= °7544 ,, 
Number of coils . n =1217. 
pz calc. =380 cos 0—30+4 1770{sin 6+4 sin 20}, 
where 
G 
6= —— decrees. 
1002 
p.- p- 
a. eS ie aio! (20) Dh af, 36. ies Reemenmn ieee |) [8h 
Obs. | Cale. Obs. | Cale. 
67-293| 492 | 381| — 41 || 95982 | 1557 | 1660 | +103 
29343 428 | 486 | + 58 10413 1531 | 1884 | —147 
2174-7 1288 | 1278 | — 10 11511 1104 | 1357 | +2538 
2337°5 1176 | 13438 | +167 12148 799 |} 953 | +154 
39490 1766 | 18238 | + 57 13246 666 | 569 | — 97 
4710°5 1982 | 1967 | — 15 13104 505 | 618 | +1138 
57199 2070 | 2067 | — 3 13671 508 | 466 | +108 
8677°4 1914 ; 1808 | —106 15053 1385 | 181} — 4 
8889'8 1775 | 1764 | — 11 
I. Forged Ring Best Lowmoor Iron. 
Mean diameter. . d =10°025 centim. 
Bar-thickness . . 2R= 1:293 _,, 
: es PASTA) 
Number of coils’. e = Age 
pe cale. = 250 +1800{sin 6+ sin 20+4 sin 30+ 4 sin 46}, 
where 
G 
é= desrees. 
100 = 
pi. 
38. Diffs 38. Hote ak Las 
Obs. | Cale. Obs. | Cale. 
32/944) 271 272 |} + 1 7090:9 | 2173 | 2012 | —161 
429°15 617 547 | — 70 8193°9 | 1935 | 1915 | — 20 
1321°8 1024 | 1078 | + 54 9690°8 | 1842 | 1795 | — 47 
1623°6 1427 | 1247 | —180 10400 1483 | 1730 | +247 
2395°1 1558 | 1616 | + 58 13159 1188 | 1390 | +202 
4541-5 2072 | 2116 | + 44 | 15050 818 851 | + 33 
6324-2 2080 | 2077 | — 3 || 163809 592) oF - 18 
6712°3 1993 | 2045 | + 52 || 16939 444 448; 4+ 4 
6700°1 2033 | 2046 | + 18 | 193803 155 182 | + 37 | 
