soil. 93 



The column headed Remarks should receive the record of 

 observations of halos, sudden changes of wind or temperature, 

 thunder-storms, rain or snow falls, and other noteworthy 

 or unusual phenomena. 



Excellent practice in comparing, relating and judging will 

 frequently be afforded by noting those conditions which are 

 usually followed in a day or two by rain, cold weather, or 

 clearing skies. 



In a rural school all the pupils in the Second Class may be 

 observers during one week; those in the Third Class the 

 following week, and so on. 



Soil. — Have a hole, with vertical sides, dug in the ground 

 to the depth of a foot or two. This may usually be done in 

 some corner in the school-yard or at a convenient place outside 

 of it. The digging of the hole will be fun to the boys of this 

 grade while the other pupils are observing. Changes in the 

 color and texture of the soil will usually be evident. Probably 

 the surface layer is quite dark in color, below it a layer, some- 

 what paler will appear, and below that a yellowish or pale- 

 grey or dark-red soil known as the subsoil. In some places 

 gravel or hard-pan, or shale or even rock will be reached 

 within a foot or two of the surface. 1 The pupils will note the 

 color, feel the texture, and measure the depth of each layer. 

 The series will probably be leaf-mould, loam, subsoil. Some- 

 thing of the origin of soil may be learned by observation, much 

 more in some localities than in others, but in all more or less 

 information will have to be given if the origin is studied in 

 this grade. 2 Pupils ought to learn in some way that the sub- 

 soil and a large part of the surface soil are derived from the 

 disintegration of rocks effected by such agencies as carbon 

 dioxide, rain and water currents, wind and climatic changes, 

 frost and ice. Three important soil-forming rocks are quartz, 

 feldspar and limestone. Samples of these and other soil- 



1 See soil boxes, Nos. 1 and 3, opposite page 46. 2 See Field Excursion, page 165. 



