APPENDICES. 



A (page 13). 



MRS. SOMERVILLE, in her book, " Connexion of the Physical 

 Sciences/' says, pp. 284285, (t On land the temperature 

 depends upon the nature of the soil and its products, its 

 habitual moisture or dryness ; " and, after describing the 

 effects of the Sahara in raising the temperature, says : " On 

 the contrary, vegetation cools the air by evaporation, and the 

 apparent radiation of cold from the leaves of plants, because 

 they absorb more caloric than they give out ; " and again says : 

 " Forests cool the air also, by shading the ground from the 

 rays of the sun, and by evaporation from the boughs." On 

 page 233 we have : " The radiating power of a surface is 

 inversely as its reflecting power, and bodies that are most 

 impermeable to heat, radiate least ; " and on page 248 : 

 " When radiant heat falls upon a surface, part of it is reflected, 

 and part of it is absorbed ; consequently, the best reflectors 

 possess the least absorbing powers." 



B (page 51). 



Some better method of disposal of town filth should be 

 adopted than polluting rivers with it. Let it be applied to 

 fields surrounded by ridges from which there is no escape by 

 surface-drainage, so that it cannot fall into the rivers, and let 

 the amount applied to the land be not in excess of what crops 

 grown on the land can assimilate, and all will be well. In 

 India, the high price of fuel increases river-pollution. The 



