. Laboratory exercises in elementary physics. and the line correspond-ing to the lowest point of the meniscus is taken as thelevel of the liquid. The cylinder must be placed on afirm horizontal surface, and the eye brought to the levelof the meniscus and directly opposite the scale. In a represents the correct method of reading, b and cthe incorrect, b would give a reading greater and c lessthan the true one. Errors caused by failure to read ascale with the lrne of sight in the proper position are saidto be due to Parallax. The following method will avoidsuch errors: Take a piece of sti
. Laboratory exercises in elementary physics. and the line correspond-ing to the lowest point of the meniscus is taken as thelevel of the liquid. The cylinder must be placed on afirm horizontal surface, and the eye brought to the levelof the meniscus and directly opposite the scale. In a represents the correct method of reading, b and cthe incorrect, b would give a reading greater and c lessthan the true one. Errors caused by failure to read ascale with the lrne of sight in the proper position are saidto be due to Parallax. The following method will avoidsuch errors: Take a piece of stiff paper about 1J X 4 inches, beingsure that the upper edge is clean and straight. Wrapitaround the cylinder, and allow a portion to project, asshown in Fig. 48. Grasp the projecting portion with thefinger and thumb, taking care that the upper and lower DETERMINATION OF VOLUMES. are even with each other. Draw the paper tightlyaround the cylinder, and move it until, on sighting acrossthe top edge from one side to the other, the meniscus just. touches it; Fig. 49. In this position the sight is the upper edge of the paper is just on a line of thescale, this gives the reading; but if not, the fraction mustbe estimated by the eye and expressed as a decimal. Sup-pose it comes, as in Fig. 50, between the 17 and 18 line. Ifhalf-way between, read ; if one third the way, ;if two thirds, ; if three fourths, ; etc. On thegraduates commonly used remember that the space betweentwo lines is half a cubic centimeter. Hence, if half-way,read ; if one fourth above, cu. cm.; etc. As a 70 MENSURATION. rule, any scale can be read to one tenth of its smallestdivision. When there is occasion to read mercury in a
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectphysics
