DIY History | Transcribe | Scholarship at Iowa | Theory of the astronomical transit instrument applied to the portable transit instrument Wuerdemann no.26: a compilation from various authorities, with original observations by Harry Edward Burton, 1903 | Theory of the astronomical transit instrument applied to the portable transit instrument Wuerdemann no. 26: a compilation from various authorities, with original observations by Harry Edward Burton, 1903, Page 22

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Theory of the astronomical transit instrument applied to the portable transit instrument Wuerdemann no.26: a compilation from various authorities, with original observations by Harry Edward Burton, 1903

Theory of the astronomical transit instrument applied to the portable transit instrument Wuerdemann no. 26: a compilation from various authorities, with original observations by Harry Edward Burton, 1903, Page 22

turning the alidade tangent screw forward we moved the gear of the [?] and hence the relative position of the two gears. The number of divisions of the scale traversed by the level corresponds to the number of second of [?] thru which the gear of the circle has turned, relative to the gear of the [?].
Before computing N'-S'/2 and adding it to S-N/2, we should turn the declination tangent screw forward to send the bubble southward again. This screw does not change the relative position of the gears of the [?] and circle and the number of divisions passed over by the bubble is in this case not recorded. After the bubble has come to rest read the ends and proceed as before. 
Now S-N/2 + N'-S'/2 = N'-N/2 - S'-S/2. For the reason that the number of divisions passed over by the bubble is given by one half the difference of the north readings [minus?]

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turning the alidade tangent screw forward we moved the gear of the [?] and hence the relative position of the two gears. The number of divisions of the scale traversed by the level corresponds to the number of second of [?] thru which the gear of the circle has turned, relative to the gear of the [?]. Before computing N'-S'/2 and adding it to S-N/2, we should turn the declination tangent screw forward to send the bubble southward again. This screw does not change the relative position of the gears of the [?] and circle and the number of divisions passed over by the bubble is in this case not recorded. After the bubble has come to rest read the ends and proceed as before. Now S-N/2 + N'-S'/2 = N'-N/2 - S'-S/2. For the reason that the number of divisions passed over by the bubble is given by one half the difference of the north readings [minus?]