+-------+-------++-------+-------++-------+-------++-------+-------+ |Height.|Radius.||Height.|Radius.||Height.|Radius.||Height.|Radius.| +-------+-------++-------+-------++-------+-------++-------+-------+ | 0 | 21·000|| 31 | 14·800|| 62 | 11·426|| 93 | 9·305 | | 1 | 20·720|| 32 | 14·660|| 63 | 11·343|| 94 | 9·250 | | 2 | 20·447|| 33 | 14·523|| 64 | 11·261|| 95 | 9·195 | | 3 | 20·182|| 34 | 14·389|| 65 | 11·180|| 96 | 9·141 | | 4 | 19·923|| 35 | 14·257|| 66 | 11·100|| 97 | 9·088 | | 5 | 19·671|| 36 | 14·127|| 67 | 11·021|| 98 | 9·035 | | 6 | 19·425|| 37 | 14·000|| 68 | 10·944|| 99 | 8·983 | | 7 | 19·185|| 38 | 13·875|| 69 | 10·867|| 100 | 8·931 | | 8 | 18·951|| 39 | 13·752|| 70 | 10·792|| 101 | 8·880 | | 9 | 18·723|| 40 | 13·632|| 71 | 10·717|| 102 | 8·830 | | 10 | 18·500|| 41 | 13·513|| 72 | 10·644|| 103 | 8·780 | | 11 | 18·282|| 42 | 13·397|| 73 | 10·571|| 104 | 8·730 | | 12 | 18·070|| 43 | 13·282|| 74 | 10·500|| 105 | 8·681 | | 13 | 17·862|| 44 | 13·170|| 75 | 10·430|| 106 | 8·633 | | 14 | 17·659|| 45 | 13·059|| 76 | 10·360|| 107 | 8·586 | | 15 | 17·461|| 46 | 12·950|| 77 | 10·291|| 108 | 8·539 | | 16 | 17·267|| 47 | 12·843|| 78 | 10·224|| 109 | 8·492 | | 17 | 17·077|| 48 | 12·738|| 79 | 10·157|| 110 | 8·446 | | 18 | 16·891|| 49 | 12·634|| 80 | 10·091|| 111 | 8·400 | | 19 | 16·710|| 50 | 12·532|| 81 | 10·026|| 112 | 8·355 | | 20 | 16·532|| 51 | 12·432|| 82 | 9·962|| 113 | 8·310 | | 21 | 16·358|| 52 | 12·333|| 83 | 9·898|| 114 | 8·266 | | 22 | 16·188|| 53 | 12·236|| 84 | 9·835|| 115 | 8·222 | | 23 | 16·021|| 54 | 12·141|| 85 | 9·774|| 116 | 8·179 | | 24 | 15·857|| 55 | 12·046|| 86 | 9·712|| 117 | 8·136 | | 25 | 15·697|| 56 | 11·954|| 87 | 9·652|| 118 | 8·094 | | 26 | 15·540|| 57 | 11·862|| 88 | 9·593|| 119 | 8·052 | | 27 | 15·386|| 58 | 11·773|| 89 | 9·534|| 120 | 8·010 | | 28 | 15·235|| 59 | 11·684|| 90 | 9·476|| 120·25| 8·000 | | 29 | 15·087|| 60 | 11·597|| 91 | 9·418|| ... | ... | | 30 | 14·942|| 61 | 11·511|| 92 | 9·361|| ... | ... | +-------+-------++-------+-------++-------+-------++-------+-------+ APPENDIX, No. II. NOTES ON THE MANUFACTURE OF PARABOLOÏDAL REFLECTORS, from Information furnished by Mr JAMES MURDOCH, OF THE NORTHERN LIGHTS SERVICE. [Illustration: Fig. 99.]