SUGGESTIONS FOR WEATHER STUDY. 317 



moderate breeze (corresponds to a velocity of 14 miles per 

 hour), strong breeze (25 miles per hour), moderate gale 

 (31 miles per hour), storm (64 miles per hour). 



(c) Clouds, their identification, proportion, direction of 

 movement, height. Pupils will require with regard to this 

 to receive definite instruction from the teacher. Photo- 

 graphs are not needed by the pupils. The teacher should 

 seize the opportunity as it arises of demonstrating the 

 various simple types. 



Those which should be pointed out first are the Cirrus 

 and Cumulus. The former, popularly known as mare's 

 tail, is a very high cloud (from 27 to 50 thousand feet), 

 white, long-curled streaky bunches, feather-like. The Cirrus 

 is a cloud of ice. The Cumulus is the familiar thick heavy 

 banked-up cloud, dome- shaped above and white, generally 

 darker underneath. It is known also as wool-pack cloud. 

 Its height is given as from 4,500 to 6,000 feet. The next 

 in point of simplicity and ease of recognition is probably 

 the Nimbus or rain cloud. This cloud is dark, and from it 

 continued rain or snow generally falls ; its height is from 

 3,000 to 6,400 feet. The Stratus also, a low flat cloud, "a 

 horizontal sheet of lifted fog," below 3,500 feet, is not diffi- 

 cult to recognise. After the pupils are expert in recog- 

 nising these, other more complicated forms may, if desired, 

 be added to their list. 



The school should be equipped with the following instru- 

 ments of as satisfactory quality as possible : Barometer ; 

 Thermometers, wet and dry bulb, and maximum and 

 minimum; Eain Gauge. The classes to which work in 

 reading of instruments and recording are allotted should 

 have work assigned to them at regular intervals of plotting 

 in graphic form such items as the daily temperatures for 

 each month, maximum and minimum, the daily barometric 

 pressure, diagrams of the wind direction for each month. 

 These again might be utilised for the making of a compo- 

 site wind diagram for twelve months, and from the results 

 of a series of years the direction of the prevailing winds 

 would in course of time be exhibited on the charts (Fig. 170). 



