THE 



NATURE-STUDY REVIEW 



Vol. 17 



January, 1921 



No. 



A Sun-dia! made by pupils 



A Sun-Dial for the School Garden 



The construction of a san-dial and the setting it up properly 

 should be a delightful means of educating the pupils in a very 



important subject, the measuring 

 of time, — a subject which is given 

 very little thought in this day of 

 clocks and watches. Even during 

 the discussion of "time saving" 

 turning back the clock an hour, 

 very few understood its real mean- 

 ing. 



Sun-dials are very ancient of 

 origin; and probably the earliest 

 form was a pole fixed in the ground 

 with the spaces covered by its 

 shadow during the da}' divided 

 and marked by stones or in some other manner. The earliest 

 mention of a sun-dial is found in Isaiah xxxviii, 8 : "Behold, I will 

 bring again the shadow of the degrees which is gone do^vn in the 

 sun-dial of Ahaz ten degrees backward." This must have been 

 written about 700 years B. C. but we have no idea of the form of 

 this dial. The earliest dial, the construction of which we know, 

 was made by the Chaldean astronomer Berossus who lived about 

 300 B. C. and it consisted of a hollow hemisphere with its rim 

 horizontal and a bead fixed at its center which cast a shadow, the 

 path of which was an arc which was divided into twelve equal 

 parts. This form of dial was used many centuries by many ])eo- 

 ples. 



No one knows certainly wiien the first clock was invented nor 

 by whom, but the use of clocks in Europe in the 13 th century has 

 been recorded. A clock was put up in a tower of Westminster in 



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