Show DISTANCE rAER MERCURY CURY REACHES the thermometer bulb Contu contains ins enough to stretch silica while almost anyone 1 knows about the principles on which ordinary thermometers mo meters operated operate there are a number of things about the little instrument which are not generally known and which are of a great deal of interest says the boston transcript one of the most peculiar of these is the question of the length of tube which the mercury in the bulb of an ordinary thermometer would fill if it were stretched out in a single column the size of that in the tul tube most people when asked how long this would be would probably say from five to fifteen feet while as a matter of fact this column of mercury would in an extremely delicate instrument be miles in length the reason of this is that the column of mercury while it appears quite larger is really of almost infinitesimal size if the tube of a thermometer is broken one is at first at a loss to see ee where the mercury geesin goes in but a close examination will disclose a fine line much thinner than a hair running across the end of the tube and this is one end of a little slit in which the mercury rises As it has its flat side toward the eye it appears to be quite large and the convexity of the outside of the tube through which it iu is seen magnifies it and gives it that rounded appearance which is so deceptive the reason why the slit is made so small is to give the greatest ratio of result for the expansion of the mercury in in the houlb |