SECTION 22. OBSERVATION. 261 



Instead of 8 hours of play, we find therefore a maximum of 

 2 1 /* hours not accounted for; and if we allow for a little rest, 

 for family and social duties, for correspondence, etc., the 

 2 1 /* hours are easily reduced to a maximum of about 1 hour 

 for each of 4 days, and 2 hours for a 5th day, in the week. 

 Incidentally this conclusion decisively disposes of the fear lest 

 the universal introduction of the 8 hours' working day should 

 create a serious leisure problem for which elaborate preparations 

 and precautions are required. On the other hand, the younger 

 worker may find 7 hours' sleep sufficient, in which case the 

 leisure time may be increased by a full hour for all working 

 days, while older men engaged on heavy work may sleep 

 9 hours and have left no leisure at all for the greater part of 

 the week. 



125. (/) Minuteness. Observation should be minute, and 

 not only what is palpable to the ordinary observer should be 

 chronicled. Minute examination, ever increasing in delicacy, 

 as the history of the sciences illustrates, alone ensures that 

 the most important facts and factors are not mistaken or in- 

 advertently overlooked. Compare, for instance, the popular 

 contention that thought is instantaneous, with the reaction 

 times in psychology; or the well-known amorphous appearance 

 of snow-flakes, with their beautiful geometrical structure when 

 microscopically examined; or consider the delicacy of observation 

 which revealed the satellites of Mars or the many hundreds of 

 asteroids, or, more recently, the correctness of Einstein's theory 

 in regard to the influence of gravitation on light rays; or 

 ponder the fact that by suitable instruments it has been shown 

 that each plant produces an abundant quantity of heat in 

 respiration; or note the perfection of observation which teaches 

 that plants seemingly devoid of chlorophyll have the green 

 hidden by some other colour; or that some plants obtain 

 nitrogen from the air with the help of certain bacteria; or 

 imagine the action of the radium emanation in the atmosphere 

 for ever causing infinitesimal amounts of nitrogen to combine 

 with the oxygen of the air; or think of the method whereby 

 M. and Mme. Curie obtained from pitch-blende ore a crystalline 

 salt 1,800,000 times more active than Becquerel's uranium; or 

 weigh the almost infinite patience exhibited by Mendelian and 

 other experimenters; or think of the exceedingly minute analysis 

 of bodily movements by experts in scientific industry. Or con- 

 sider "letting roots grow along polished marble plates. After 

 some weeks the marble surface clearly demonstrates the dis- 

 solving effect of growing roots and root-hairs. Delicate traces 

 are everywhere etched in the marble surface, where roots have 

 come into close contact with the plate." (Frederick Czapek, 

 Chemical Phenomena in Life, 1911, p. 51.) Or note that "minute 

 traces of iron salts, scarcely to be ascertained by chemical 

 analysis, possess the power of greatly accelerating growth and 



