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spherules, supposing the least distance of distinct vision to be 7 inches, and the object to be placed (l) at the focus, (2) at the least distance for distinct vision.

Focal length
in terms of
an inch
.
No. of times that the
length of the object
is magnified
.
No. of times that
the surface is
magnified
.
——————————————————————————————
.10007.00008.00000049000064
.75009.33010.33000087000107
.50014.00015.00000196000225
.40017.50018.50000306000342
.30023.33024.33000544000592
.20035.00036.00001225001296
.15046.66047.66002181002276
.10070.00071.00004900005401
.05140.00141.00019600019881
.03233.33234.33054289054912
.02350.00351.00122500123201
.01700.00701.00490000491401

The next Table is for a person whose least distance of correct vision is 5 inches.

Focal length
in terms of
an inch
.
No. of times that
the length
is magnified
.
No. of times that
the surface is
magnified
.
——————————————————————————————
.10005.00006.00000025000036
.75006.67007.67000044000058
.50010.00011.00000100000121
.40012.50013.50000156000195
.30016.67017.67000278000312
.20025.60026.00000625000676
.15033.33034.33001111001179
.10050.00051.00002500002601
.05100.00101.00010000010201
.03166.67167.67027779028110
.02250.00251.00062500062901
.01500.00501.00250000251001
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