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 5

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 5

On transit instrument Wudermann NO.26. the vertical reach is divided into twenty-minute spaces and can be read to minutes by measure of the verier; for the verier is constructed or that twenty of its divisions, or spacers, are equivalent to nineteen twenty-minute spaces on the circle. Thus, if dr=d division of the vernier and dc=(20')=a division of the circle, we have 20dv=19dc; where dr=19/20dc and dc-dr=dc/20=r. So if we bring the zero of the verier into coincidence with a mark on the circle, e.g.41 40', the circle reading will be 41 40'. If we bring the first division mark of the vernier into coincidence with the 42 mark on the circle, the zero of the vernier will be one minute in advance of 41 40' and the circle reading will therefore be 41 41'. In like manners, bringing the second division mark of the vernier into coincidence with the 42 20' mark on the circle will make the circle read 41 42'. As follows that if the zero of the vernier lies between two marks of the circle, r1 and r2, where r2>r1, and if the math....

On transit instrument Wudermann NO.26. the vertical reach is divided into twenty-minute spaces and can be read to minutes by measure of the verier; for the verier is constructed or that twenty of its divisions, or spacers, are equivalent to nineteen twenty-minute spaces on the circle. Thus, if dr=d division of the vernier and dc=(20')=a division of the circle, we have 20dv=19dc; where dr=19/20dc and dc-dr=dc/20=r. So if we bring the zero of the verier into coincidence with a mark on the circle, e.g.41 40', the circle reading will be 41 40'. If we bring the first division mark of the vernier into coincidence with the 42 mark on the circle, the zero of the vernier will be one minute in advance of 41 40' and the circle reading will therefore be 41 41'. In like manners, bringing the second division mark of the vernier into coincidence with the 42 20' mark on the circle will make the circle read 41 42'. As follows that if the zero of the vernier lies between two marks of the circle, r1 and r2, where r2>r1, and if the math....