340 



oi) germination of freezing the seeds just before they were ready to ger- 

 ]ninate, it was found that seeds soaked until ready to germinate and 

 then kept frozen for a length of time required a longer time to com- 

 plete, the germination than did those that had not been frozen; the 

 I'etardation increased in proportion to the duration of the freezing, 

 amounting to about twelve daj's for a freezing of twenty-four days. 

 The percentage of thawed-out seeds that germinated was also smaller 

 in proportion as the duration of the freezing increased, being -t-t per 

 cent for a duration of tw^enty-four daj'^s. 



Changes in the seeds produced hy frost. — After the seeds had 

 remained frozen for ten to twelve days a white, glutinous material 

 oozed out at every slight break in the coat of the seed. A micro- 

 scopic examination showed that the cell w^all and starchy protoplasm 

 was almost entirely disorganized, but the starch granules themselves 

 were entirely unaffected. Strange to say, the power of the seeds to 

 germinate was not destroyed by this. (Agr. Sci., Vol. IV, p. 337.) 



Protection from frosts. — The formation of artificial clouds of 

 smoke for the protection of plants from frost is generally successful, 

 and should be resorted to in critical cases; thus, in a vineyard at 

 Pagn}' about 3 a. m. of May 13, 1887, wdien the temperature was 3° F. 

 below freezing, liquid t^' was ignited, which had been poured into 

 tin boxes, as also pieces of solid tar. Large clouds of smoke quickly 

 enveloped the vineyard ; the fires lasted for about two hours, but the 

 smoke lasted considerabl}^ longer. All injury to the plants by frost 

 was entirely prevented. (Agr. Sci., Vol. 1, p. 172.) 



INJURIES AND BENEFITS DUE TO WIND-BREAKS. 



Protection against the injurious effects of wind may be obtained 

 by the use of wind-breaks, which are usually made b}^ planting a 

 couple of rows of trees on the windAvard side of the field, or by so 

 arranging the plantation that the hardiest and most vigorous decidu- 

 ous trees are on the windward side. According to Bulletin No. IX 

 issued by the Cornell University Agricultural Experiment Station, 

 the benefits derived from Avind-breaks are the following: Protection 

 from cold, diminution of evajjoration from soil and plants, diminu 

 tion of the number of windfalls, diminution of liability to mechanical 

 injury to trees, retention of snow and leaves, facilitation of outdo(n- 

 labor, protection of blossoms from severe winds, protection of trees 

 from deformity of shape, diminution of evaporation and drying up 

 of small fruits, diminution of the encroachment of sand or the loss 

 of dry soil or the scattering of rubbish,, increased rapidity of m.atur- 

 ity of fruits, and encouragement of birds that are beneficial to 

 agriculture. 



Among the organisms arrested by wind-l)reaks and usually reckoned 

 as an injurious climatic influence are the fungi or the spores of fungi. 



