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. Sketch 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 
