Q 8 the popular science monthly. 



came in contact with the moist .air over the stream. The following 

 morning all the trees, especially the pines, were covered with a heavy- 

 hoar-frost, but on the land-side only, not on the water-side. On ex- 

 amining the ice-spicules, they were found to be perfectly crystalline, 

 with angles of from 60 to 120, and the long needles were made up 

 of minute crystals set one upon another, and on one side resembling a 

 flight of stairs. The particles of water floating in the air were, of 

 course, of the temperature of the atmosphere, and consequently below 

 the thawing-point. So soon as they came in contact with the points 

 of the ice-spicules, they solidified, just as very cold water will when it 

 is touched with ice. If the particles of mist had been changed into 

 ice while still floating in air, they would have gathered upon the 

 spicules of the pines in the shape of irregular pulverulent conglomer- 

 ates, but would not have formed crystals. The plainly crystalline 

 form of the ice-spicules shows, beyond a doubt, that the particles of 

 mist were fluid at 4 Fahr. From these facts it follows that the 

 minuter the particles of a liquid body are, the further they can be 

 brought beneath their thawing-point without freezing. 



If, now, we make an application of these facts to the above phenom- 

 ena of organic Nature, we find that the reason why watery. humors of 

 pupa?, eggs, leaves and shoots, do not freeze, is because the cells con- 

 taining these humors are very minute : in other words, the larger the 

 cells the more quickly will plants freeze. It is well known that the 

 young sprouts of vines, potatoes, and other plants, very readily freeze 

 under a light frost, as was the case on May 12th of last year. Now, 

 these young sprouts of vines are extremely juicy, containing a great 

 quantity of water, and consequently but little cellulose. And, al- 

 though the vines of the preceding year stood a winter temperature of 

 2 Fahr. without freezing, the sprouts of the self-same plants were 

 frosted at 21 Fahr. Freezing expands the water and bursts the cells, 

 and the break-up of the texture stops the process of growth. The 

 buds of vines are more watery than the ligneous vines themselves. 

 Hence, too, last winter, on the night of December 7th, many buds 

 were frozen, while the vines were unhurt. On a vine eight feet in 

 length, one of the latest of the buds rested on a wall covered with 

 snow, and this shot forth in the spring, though all the other buds on 

 the vine failed." It was the coming of the frost so early in December 

 'that made it so destructive, for the vines grow ever drier, and the sap 

 tends toward the roots, from the beginning of autumn. This process 

 had not gone so far in December as it would have gone in the first 

 'half ef January, when usually the heavy frosts set in. Those branches 

 whose buds are destroyed by frost, afterward die of their own accord, 

 "because the sap is unemployed, and the work of the leaf has ceased. 

 Several of the vines remained green, and flourished toward the end of 

 April on being pruned, but afterward dried up, as their buds were 

 without life. 



