266 NA TURE-STUD Y RE VIE W [ 6 9: -Dec. 1910 



for the clay. The flying arrow indicates the wind, as on the wall 

 chart, or the direction of the wind ( named, of course, from its 

 source) may be written. 



The reading of the thermometer is easily acquired by pupils 

 who can "count to one hundred". An alcohol thermometer with 

 the liquid brightly colored is preferable to a mercury tube, and 

 a large instrument with large degree spaces — such as is often 

 employed for advertising purposes — has evident advantages for 

 work with children. Relative terms may be used at first, but 

 for a short time only, to characterize the height of the column ; 

 and the Fahrenheit scale is developed upon the blackboard, the 

 pupils representing thereon the position of the mercury for the 

 day. A still better plan is to prepare a large cardboard panel 

 on which a thermometer bulb and scale are pictured, the bulb 

 being colored red and the scale black. A strip of red "baby 

 ribbon" representing the column, disappears through a slit in the 

 bulb and is attached behind the cardboard to a white strip which 

 passes through a slit at the upper end of the scale where, attached 

 to the red piece, it completes an endless bi-colored belt which 

 can be adjusted daily by the pupil to picture the temperature 

 reading for the day. The white ribbon is "invisible" upon the 

 scale, and the end of the red ribbon indicates the top of the 

 column. This device is easily manipulated and is useful in drill- 

 ing the class upon the reading of the instrument. A few obser- 

 vations, in winter time, suffice to fix in the mind the freezing 

 point and the temperature suitable for the room. The increased 

 temperature due to the entrance of a number of warm human 

 bodies into the room is a point of interest and affords an ap- 

 proach to studies of ventilation, body temperature, "warm- 

 blooded" and "cold-blooded" animals, liberation, and related 

 topics. 



By picturing a series of five thermometers upon a common 

 horizontal scale drawn across the board, representing the read- 

 ings for five consecutive days, and then drawing a line connect- 

 ing the tops of the columns, a picture of the temperature for the 

 week (temperature curve) is developed. The writer has con- 

 ducted this exercise with a third grade class with the result that 

 in a twenty-minute lesson every pupil quickly grasped the idea 

 of the graph and eagerly interpreted different types of tempera- 

 ture curve drawn without any supporting scale. Thus, from a 

 horizontal line is read "a day in which the thermometer stayed 

 the same all the time," while a curve indicating a mid-day maxi- 



