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 17

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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 17

the elevation of the end of the level. By accertaining the angle corresponding to a motion over one direction of the graduated scale, we may, by reading the two ends of the level bubble, determine the amount by which the axis is out of level. 
It will be noticed that the bubble has a double outline; so in reading the two ends of the bubble we should use the same outline for both readings, and for all readings. 
Adjustments of the stride level. 
(from JF hayford's Report)
Since the level is used for testing, the horizontality of the axis as well as for leveling is properly, when it is placed on the axis the tube should be parallel to the latter. If such is the case;-
First. The bubble must be in the middle of the tube when the axis is horizontal. The axis being approximately horizontal, place the level on it, read the scale, reverse the level,

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the elevation of the end of the level. By accertaining the angle corresponding to a motion over one direction of the graduated scale, we may, by reading the two ends of the level bubble, determine the amount by which the axis is out of level. It will be noticed that the bubble has a double outline; so in reading the two ends of the bubble we should use the same outline for both readings, and for all readings. Adjustments of the stride level. (from JF hayford's Report) Since the level is used for testing, the horizontality of the axis as well as for leveling is properly, when it is placed on the axis the tube should be parallel to the latter. If such is the case;- First. The bubble must be in the middle of the tube when the axis is horizontal. The axis being approximately horizontal, place the level on it, read the scale, reverse the level,