. Time and its measurement . zontal Sundial for-43 The reason that the table given hereis convenient for setting clocks to meantime is that a minute is as close as adial can be read, but if you wish forgreater accuracy, then the almanac,which gives the equation of time toa second for each day,.will be reason that these noon-mark dialsare better than ordinary commercialdials is that they are larger, and stillfurther, noon is the only time that anydial is accurate to sun time. This is be-cause the suns rays are refracted ina variable manner by our atmosphere,but at noon this refractio
. Time and its measurement . zontal Sundial for-43 The reason that the table given hereis convenient for setting clocks to meantime is that a minute is as close as adial can be read, but if you wish forgreater accuracy, then the almanac,which gives the equation of time toa second for each day,.will be reason that these noon-mark dialsare better than ordinary commercialdials is that they are larger, and stillfurther, noon is the only time that anydial is accurate to sun time. This is be-cause the suns rays are refracted ina variable manner by our atmosphere,but at noon this refraction takes placeon a north and south line, and as thatis our noon-mark line the dial reads. correctly. So, for setting clocks, thecorner of your house is far ahead of themost pretentious and expensive Fig. 4 is shown a modern horizontaldial without the usual confusing orna-mentation, and in Fig. 5 it is shown setup on the latitude of New York Cityfor which it is calculated. This showsclearly why the edge EG of the stylewhich casts the shadow must be par-allel to the earths axis and why a hori-zontal dial must be made for the lati-tude of the place where it is set (i is the same dial only the linesare laid out on a square dial plate, and
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Keywords: ., boo, bookcentury1900, bookdecade1900, booksubjectclocksandwatches
