Retardation of Bloom. 43 



stated, excepting on the basis of a careful study 

 extending over several years. The lake breeze of 

 the day must moderate the daytime temperature; 

 and the land breeze of the night may, in some 

 cases, so keep the air in motion as to prevent 

 frosts. That there is a marked influence upon cli- 

 mate as a result of the peculiar conditions of 

 topography and neighborhood of water, is evident at 

 the very first. Sketeh maps show that the mean 

 annual rainfall is greater on the escarpment than on 

 the lake plain, and that the mean annual tempera- 

 ture of the hills is lower than that near the lake." 



The particular influence which the water exerts 

 over frost injury in spring is often due more to the 

 retardation of the period of bloom than to the actual 

 prevention of frost, although its influence in the 

 latter direction is important. The lands adjacent to 

 the water ordinarily warm up later in spring, and 

 the trees are not likely, therefore, to swell their buds 

 until danger of serious frosts is past. The amount 

 of this retardation of bloom is often as great as 

 ten to twenty days within a stretch of fifteen or 

 twenty miles from a large body of water. It is well 

 known that the danger from frosts is greatest in 

 mild climates, in which "warm spells" are likely to 

 occur in late winter or early spring. In the central 

 and southern states, this frost injury following a 

 period of warm weather is commoner than true 

 winter -killing, whilst in the northernmost states and 

 Canada serious injury to the trees from late spring 

 frosts is comparatively infrequent. In the northern 



