September 15, 1897.] 



Garden and Forest. 



361 



yellow Columbine of spring seems almost sturdy if we 

 think of it in comparison, and even the Harebell is not so 

 frail. On woodland banks or open meadows it is ex- 

 quisite indeed, and if rightly treated indoors it preserves 

 its charm. Nothing else should be mixed with it, but if 

 a loose bouquet of it is put in a thin white glass vase, the 

 beauty of the open flowers and the spark-like effect of the 

 unopened ones will delight the eye for a few brief hours. 

 On the morrow it will have withered. But who would 

 expect a flower like this to " last " as does a Golden- rod or 

 a Closed Gentian ? The only marvel is how its fairy-like 

 frame can furnish sap enough for the elaboration of its 



lovely flowers. 

 Tuxedo Park, n. y. M. Cr. I an Rensselaer. 



Some Facts about Frost Prevention. 



IN few countries have methods for the prevention of 

 injury by frost been so systematized as in France. The 

 nature of many of the crops and the peculiar situations 

 they often occupy have demanded extreme vigilance at 

 critical periods or total loss has followed. Prior to the 

 comprehension of the principles involved in these methods, 

 and even at the present day in less enlightened communi- 

 ties, the disturbing cause of frosts has been that arch- 

 enemy of agricultural practice, the moon. This innocent 

 luminary has, in the past, exercised as baneful an influence 

 over the fruit crops of France as it does in certain benighted 

 Potato-fields in America at the present day. It was not 

 until long after the physicist Arago had explained the 

 cause of these late spring and early autumn frosts that the 

 superstitious peasantry gradually lost faith in the blighting 

 efficacy of moonbeams. These frosts, Arago demonstrated, 

 are due to the rapid radiation of heat from the earth, always 

 augmented by still air and a clear sky, but retarded by 

 clouds and wind, the former acting as a blanket to check 

 the escaping heat, the latter preventing the air from settling 

 in pocket-like formations in the general contour of the land. 



Coverings of paper and other materials commonly used 

 to protect flower-beds would in themselves be too slight a 

 protection but for the check they give to the heat and 

 moisture escaping from the ground. The relatively high 

 temperature maintained under these coverings is due to 

 the continual evolution of heat which accompanies the 

 condensation of moisture. To protect small areas or a 

 limited number of specimens, French gardeners use straw 

 mattings, bell-jars, various kinds of frames and screens, 

 which latter are, as at Montreuil (in the vicinity of Paris), 

 hooked to permanent or temporary supports. This last 

 method was brought to France, by way of England, from 

 Scandinavia, where it has been used time out of mind for 

 the protection of wall fruits. 



A unique method for tree protection is the hanging of a 

 thick rope from a high branch of the tree, the lower end 

 being in a pail of water. Jlie Farmers' and Planters' 

 Encyclopedia remarks that "should a slight frost take 

 place at night it will not in the smallest degree affect the 

 tree, while the surface of the pail, which receives the rope, 

 will be covered with ice ; the water placed in another pail 

 by the side of it, by way of experiment, may not from the 

 slightness of the frost, have any ice on it at all." In this 

 case the rope, by exposing a large surface to the air, aids 

 the evaporation of the water carried up by capillarity, and 

 the heat evolved by the condensation of this water among 

 the foliage raises the temperature above the line of danger. 



When plants are covered by hoar frost they may yet be 

 saved, say Decaisne and Naudin {Ma?iual del' Amateur des 

 Jardins, vol. i., page 624), by sprinkling them freely with 

 water, which loosens and removes the ice and gradually 

 raises the temperature of the plant to its normal degree of 

 heat. Doubtless this is a somewhat sweeping assertion, 

 since the damage may have occurred at the time of freez- 

 ing. And damage at the time of freezing seems all the 

 more probable from the following experiment recorded by 

 Stewart. Two sets of smudges were placed in different 



vineyards equally exposed. In the first, they were lighted 

 one hour before sunrise ; in the second, when the tempera- 

 ture reached the freezing-point. In the former the buds 

 were frost-bitten ; in the latter, unhurt. Some plants can 

 stand a good deal of frost without being injured, while 

 others are permanently disabled by temperatures not below 

 the freezing-point. 



The practice of smudging is more ancient than is usually 

 supposed. De Serre, a prominent agriculturist of the six- 

 teenth century, recommended it, and it is even said to have 

 been favorably spoken of by Pliny. In Wurtemberg, in 

 1796, the men were divided into companies of about 

 twenty, under a captain, to protect certain assigned dis- 

 tricts, and were called out by an alarm given by a regular 

 watchman. This service was compulsory, since article 

 seven of the rules reads that whoever "shall refuse to 

 obey, shall be prosecuted before the bailewick, and receive 

 exemplary punishment." 



Even long after the practicability of frost prevention had 

 been demonstrated, fruit-growers, instead of testing the 

 methods, as a rule continued to accept its ravages as a 

 thing to be expected, but not avoided. But of late years 

 they have commenced to see the benefits derived, and the 

 use of smudges has been growing in popularity. These 

 are made of almost any substance, such as dampened 

 straw, manure, tar, sawdust, crude kerosene ; in fact, any- 

 thing which will produce a smouldering fire with much 

 smoke and little blaze. Besides these substances, various 

 compositions have been put upon the French and other 

 markets. One of these, Testout's (considered the best), is 

 sold in the form of bricks, which weigh sixteen pounds, 

 and cost about fifteen cents each. They are placed about 

 thirty feet apart, and lighted at the approach of danger. A 

 tract of about 2,200 acres may be protected by 300 of these 

 bricks at a cost of about one cent per acre per hour for the 

 material. The smudge formed will, in still weather, be 

 effective for about two hours, when it may be renewed if 

 necessary. In many orchards and vineyards these smudges 

 are fired automatically by various devices. These are not 

 often satisfactory, since the machine lights all fires at once, 

 in which case, if there be but a slight breeze, the smoke 

 from the leeward smudges is lost, while that from the wind- 

 ward fires is liable to be too much diluted with air to be 

 effective. 



A district rather than an isolated plantation should be 

 protected. This is best accomplished by organized effort 

 on the part of all proprietors owning crops liable to injury. 

 One such company of 115 growers was formed at Moulis, 

 in Medoc. Their operations were very successful. The 

 cost of protection was only twenty-five cents a thousand 

 vines for the season, a figure which could not be reached 

 by individual protection. 



The success attending the application of protective 

 methods may be still further seen in the following cases : 

 At Lussac, in Medoc, on April 21st, 18S7, the trellis wires 

 were covered with ice. Smudges were lighted at two a. m., 

 and not only were the crop and the vines saved, but even 

 the tenderest foliage covered by the cloud was uninjured. 

 At Cornell University, in the autumn of 1S96, the whole of 

 the Dahlia and Canna plantations, which were in a hollow 

 from which the cold air could not escape, were success- 

 fully protected by the smudge and water methods. At the 

 Michigan Agricultural College, a few years ago, beds of 

 Geranium and Coleus were saved by the water method, 

 and were in fine condition some weeks after even less ex- 

 posed beds had succumbed. 



This water method consists simply in a liberal drenching 

 of the plants and the ground on the evening when frost is 

 expected. If there be a rise of ground in the immediate 

 vicinity of the plants to be protected, it should also be 

 wetted down so that the air which flows over it toward the 

 plants will be saturated with moisture. When the tempera- 

 ture falls, water vapor is condensed, a large amount of 

 latent heat is evolved and the temperature of the air is 

 raised. Of course, when general freezes overspread a wide 



