MEASURES OF TIME. 



and wasteful learning, the other knowing no burden of heavy tedious 

 penury. These time ambles withal. 



" Orl Who doth he gallop withal ? 



11 Ros. With a thief to the gallows : for though he go as softly as foot 

 can fall, he thinks himself too soon there. 



" Orl. Who stays it withal ? 



" Ros. With lawyers in the vacation : for they sleep between term and 

 term, and then they perceive not how time moves." 



SHAKSPEARE, As You Like It, Act III. Scene 2. 



6. A succession of thoughts and perceptions floating at hazard 

 through, the mind, or excited casually and without regularity hy 

 external objects, produces a perception of time, but affords no 

 measure of it ; just as the general view of a landscape produces 

 the impression of a certain progression of distances among the 

 objects composing it, without, however, supplying the means of 

 estimating with numerical precision such distances. 



A progression of events or perceptions . which would supply a 

 measure of time, must be absolutely uniform and regular. In 

 such case the number of repetitions of the same event or pheno- 

 menon found between any two points of the series becomes 

 the measure of the interval of time which has elapsed between 

 them. 



7. The series of phenomena adopted by mankind as measures 

 of time have been either natural or artificial. Natural measures 

 of time consist of regularly recurring periodical phenomena, 

 which are easily and universally observable by all the world, and 

 which never cease to be reproduced with the same uniformity in 

 all parts of the inhabited globe. Artificial measures are usually 

 motions which are so contrived as to be uniform so long as they 

 continue, and which, when exhausted, admit of being restored. 



Any regular periodical change, however, may serve as a 

 measure of time. Thus woodmen ascertain the age of certain 

 trees by marks upon their trunks. The ages of certain species of 

 cattle are indicated by the successive formation of rings on their 

 horns. The age of horses is ascertained by the successive dis- 

 appearance of marks from their teeth. 



If a candle in burning were consumed uniformly its decrease 

 of ^ length might be used as a measure of time. In certain sales 

 by auction, the continuance of the bidding was limited by "inch 

 of candle." 



8. But the periodical phenomena which have been most univer- 

 sally adopted in all ages and all countries as measures of time, 

 are those which were expressly assigned for that, among many 

 more important purposes, by the Omniscient, who, when he "made 

 the firmament and saw that it was good," said 



"Let there be light in the firmament of the heaven, to divide 



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