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 UNIVERSITY OF CALIFORNIA 
 
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ELECTRO-HORTICULTURE 
 
 BY 
 GEO. S. HULL, M.D., Sc.D. 
 
 PASADENA GAL. 
 
 TEbe Knickerbocker jprcss 
 i?ork 
 
COPYRIGHT, 1898 
 
 BY 
 GEORGE S. HULL 
 
 7*03-3 
 
PREFACE 
 
 ELECTRICITY is analogous to heat and light, 
 and, like them, has an influence upon the 
 growth of plants. What this is, it is the purpose 
 of the author to inquire into with his readers by 
 presenting to them a summary of what has been 
 accomplished in the comparatively new science of 
 electro-horticulture, and by discussing with them 
 the rationale of the action of electricity upon 
 vegetation. 
 
 That he may afford assistance to some who are 
 already at work, and possibly influence others to 
 investigate into this fascinating subject, is his sole 
 motive in offering to the public this monograph. 
 
 He has had in view the popular rather than the 
 scientific aspect of the subject, and hence has 
 limited himself to what he felt would most appeal 
 to the average reader. 
 
 G. S. II. 
 
 PASADENA, CAL., October i, 1898. 
 
CONTENTS 
 
 I. The Dawn of Electro-horticulture. The Appli- 
 cation of Electricity to the Stalks of Plants . I 
 
 II. Electricity from the Atmosphere Applied to the 
 Roots of Plants and to the Soil Surrounding 
 them ........ 8 
 
 IIT. Electricity from Batteries Applied to the Roots 
 
 of Plants and to the Surrounding Soil . . 14 
 
 IV. Effects of the Electric Light upon Vegetation . 19 
 V. How Does Electricity Act upon Vegetation ? . 24 
 
 VI. Some Suggestions and a Glimpse of an Electric 
 
 Farm of the Future ..... 32 
 
ELECTRO-HORTICULTURE 
 
 CHAPTER I 
 
 THE DAWN OF ELECTRO-HORTICULTURE. THE 
 APPLICATION OF ELECTRICITY TO THE 
 STALKS OF PLANTS 
 
 THE use of electricity in horticulture, while 
 seemingly of recent years, had its small be- 
 ginning long before the invention of the dynamo, 
 and even antedated several years Franklin's im- 
 portant discovery, in 1752, by which he startled the 
 scientific world with the announcement that he had 
 drawn the " electric fluid " from the clouds by 
 means of a kite, and had proved it to be identical 
 with the electricity of the Leyden jar. As early as 
 1746, the very year which saw the invention of the 
 famous Leyden jar, Von Maimbray, of Edinburgh, 
 began to study the effects of electricity upon plant 
 life, his first experiment being with two young myrtle 
 trees. He simply passed the current down through 
 them to the soil, and found that it stimulated their 
 growth. Soon experimenters upon the continent 
 were at work along the same line, and their results 
 
were such that they readily agreed with him that 
 electricity exerted a favorable influence upon vege- 
 tation. They, like Von Maimbray, passed the 
 electricity, developed mainly by friction, through 
 the stalks of plants to the soil. The machines they 
 used to develop the current were so crude, and 
 their experiments conducted upon such a small 
 scale, that but little advance was made upon the 
 initial experiments, and the interest accordingly 
 waned. 
 
 In 1783, Abbot Bertholon became interested in 
 the subject, and his investigations soon convinced 
 him that electricity was decidedly useful in the 
 maturing of plants. His enthusiasm reached a 
 high pitch, and he gave vent to it in a book, Con- 
 cerning Electricity in Plants. He devoted the larger 
 part of it to reporting the results of his experiments, 
 and the remainder to the description of the appli- 
 ances used in furnishing electricity to the plants. 
 
 We shall briefly describe two of these devices. 
 One consisted of an insulated rod, supported ver- 
 tically, holding up some points in the air and 
 terminating in other points directly over the plant; 
 his intention being to draw down some of the elec- 
 tricity in the atmosphere and pass it through the 
 plant into the ground. The other was more in- 
 genious and complicated, and furnished electricity 
 on a much larger scale. A barrel of water was 
 placed on a cart; beside it stood the operator on an 
 insulated stool. His body was connected by means 
 of an insulated wire with the positive pole of a 
 frictional-electric machine in action. As he dipped 
 
water out of the barrel by means of a large sprink- 
 ling-can it became charged with electricity from 
 the machine. By sprinkling it upon the plants 
 while the cart was being driven among them, the 
 current was delivered to them by the water, and 
 passed through them to the soil. 
 
 These currents of high electromotive force (pres- 
 sure), generated by the frictional-electric machines 
 used by Bertholon, could readily pass through the 
 water l to the plants, and through them to the 
 ground. 
 
 While Bertholon was observing the effects of de- 
 vices which gave a much larger supply of electricity 
 to plants than they could get from the atmosphere, 
 Gardini, of Turin, was pursuing an opposite course 
 by watching the results of experiments which en- 
 tirely removed plants from the influence of atmo- 
 
 1 That water will conduct electricity many persons have 
 learned to their surprise when they have attempted to remove 
 a coin from a bowl of this fluid which has been connected 
 with one of the poles of an induction coil, their bodies having 
 been connected with the other pole. Firemen have also 
 learned that it is not safe to throw a stream of water over live 
 electric wires, because the insulation may have been burned 
 off, or removed in other ways, and a dangerous and perhaps 
 fatal current may escape down the stream of water to their 
 bodies. That fertile genius, Mr. FMison, not long ago start- 
 led us by suggesting that we utilize the conducting power of 
 water in modern warfare. He spoke of rendering a fort im- 
 pregnable by means of such simple machinery as a powerful 
 force-pump to propel streams of water, and a dynamo to fur- 
 nish deadly currents of electricity to them. But a handful of 
 men would be required to run this machinery and direct the 
 electrified streams of water- upon the advancing columns of 
 
spheric electricity. The former claimed that by 
 increasing the supply of electricity he could 
 markedly hasten the maturing of plants, and the 
 latter that by depriving plants of it, he could very 
 materially retard their growth. Gardini's method 
 was to protect plants from the influence of the at- 
 mospheric electricity by covering them with cages 
 of wire gauze, and then to compare them with 
 others exposed to the action of the electricity in 
 "the atmosphere. The wire gauze which surrounded 
 the plants conducted the atmospheric electricity 
 away from them to the ground, and the result was 
 that the plants drooped; when he removed the wire 
 cages they revived again. He gave his conclusions 
 as follows: 
 
 " i. Atmospheric electricity exerts considerable 
 influence upon the production of vegetable matter. 
 All things equal, plants will develop better every- 
 
 the enemy, mowing them down instantly. If it pleased these 
 dispensers of death within the fort, they could, by reducing 
 the strength of the current, merely temporarily paralyze their 
 foemen, and then go out and capture them ; or, if they were 
 diabolical enough to crave some sport at the expense of their 
 helpless victims, they, by still further reducing the strength of 
 the current, could cause them to throw away their weapons 
 and engage in a dance, which, while amusing to the merciless 
 men within the fort, would be anything but pleasurable to the 
 writhing humanity at the other end of the streams of electri- 
 fied water. Of course, the enemy might come clad in rubber 
 suits, or otherwise insulated ; a'nd then it would be a question 
 of strength of current on the one hand, and perfection of in- 
 sulation on the other. It is hardly likely that we shall have a 
 practical test of this matter ; it belongs more to the realms of 
 electric fancy. 
 
where where they are exposed to the action of 
 atmospheric electricity. 
 
 " 2. Plants protected from the action of the 
 atmospheric electricity have, in the same space of 
 time, given from fifty to seventy per cent, of fruit 
 and seed less than the plants placed in ordinary 
 conditions, that is to say, to which electricity has 
 free access. 
 
 " 3. The proportion of albuminous substances 
 does not appear to depend sensibly upon the influ- 
 ence of electricity, while plants that are protected 
 from it appear to contain less water and more min- 
 eral substances. 
 
 " 4. Tall plants have a harmful influence upon 
 the development of plants that grow at their base, 
 not only by depriving them of light and heat, but 
 also because they absorb atmospheric electricity at 
 their expense." 
 
 Leclerc, who was experimenting at the same 
 time, agreed with Gardini. Celi tested the matter 
 in another way. He planted three grains of corn in 
 a flower-pot, and placed it under a bell-glass. In 
 another pot of the same size, filled with the same 
 quality of earth, he planted three similar grains, 
 and placed the pot under a bell-glass of the same 
 size as the former one. He provided so that each 
 would receive the same amount of water and air. 
 Thus both were protected from the influence of 
 atmospheric electricity. He then arranged one 
 of the bell-glasses so that a wire passed through its 
 top and ended in a number of radiating points just 
 within. This wire was connected with an insulated 
 
metallic vessel near the bell-glass, from which ves- 
 sel issued a fine stream of water. The flow of 
 water electrified the vessel, and the current passed 
 down the wire and was dispersed within the bell- 
 glass. Thus one flower-pot, with its imbedded 
 corn, received a constant supply of electricity, 
 while the other received none. It was soon noticed 
 that the plants in the electrified air were growing 
 faster than the others. In ten days, the former 
 were ten centimetres high, while the latter were but 
 eight. 
 
 These experiments were largely repeated and 
 abundantly confirmed, yet there were experiment- 
 ers who reported contradictory results. Among 
 them was Ingenhouss, a high authority in vegetable 
 physiology in his time (1787). His denial that 
 electricity exerted a beneficial influence upon 
 vegetation very much chilled the enthusiasm of 
 those who were experimenting; but still the experi- 
 ments were not discontinued. 
 
 Especially interested and active became Mr. 
 Selim Lemstrom, of University of Helsingfors, who 
 had noticed that in Lapland and in Spitzbergen 
 plants grew with wonderful rapidity during the 
 short polar summer, and their flowers were more 
 brightly colored, and, if they were cereals, yielded 
 surprisingly large crops. He attributed this to the 
 fact that atmospheric electricity was more abundant 
 in the polar regions than elsewhere; he knew that 
 these regions are the peculiar homes of the aurora 
 borealis, a generally conceded electric phenom- 
 enon. Lemstrom planted seeds in pots, and put 
 
7 
 
 some of them under a system of wires with points 
 projecting downward so as to deliver the electricity 
 from the positive pole of a Holtz machine upon the 
 growing plants; the others were not exposed to the 
 current. He found in six weeks (the machine 
 being in operation five hours each day) that the 
 plants electrically treated were forty per cent, in 
 advance of the others. He also found that it did 
 not matter whether the electricity was passed down 
 through the plant or in the opposite direction. 
 
 In 1885, experiments were conducted on a larger 
 scale in the open fields in the domain of Niemis. 
 A system of insulated wires was erected over part 
 of a field of barley; at short intervals were metallic 
 points which could deliver the electricity down 
 upon the grain. This system was connected with 
 the positive pole of a four-disk Holtz machine, the 
 negative pole being connected with a zinc plate 
 buried in the earth. The machine was run eight 
 hours a day. The result was that the crop was in- 
 creased one third in the electrified part of the field. 
 Larger claims were made in the following year by 
 the experimenters at Brodtorp, who used the cur- 
 rent from four electric machines. 
 
 From the many experiments conducted by Lem- 
 strom, he concluded that electricity favorably 
 affected the growth of wheat, rye, barley, oats, 
 beets, parsnips, potatoes, radishes, celery, leeks, 
 kidney-beans, raspberries, and strawberries; while 
 carrots, rutabagas, turnips, cabbages, and tobacco 
 were more or less injured by the electric treatment. 
 
 That the results obtained by the different invest- 
 
8 
 
 igators were not always harmonious is not strange 
 when we consider that the experiments were per- 
 formed at various points on the earth's surface, and 
 that the time of day during which the current was 
 applied and the length of the application were sub- 
 ject to wide variations. 
 
CHAPTER II 
 
 ELECTRICITY FROM THE ATMOSPHERE AP~ 
 PLIED TO THE ROOTS OF PLANTS AND TO 
 THE SOIL SURROUNDING THEM 
 
 IN 1891, Paulin, of the Agricultural School at 
 Beauvais, France, began a series of experi- 
 ments near Montbrison, with the expectation of 
 drawing down the atmospheric electricity in more 
 abundant quantities than had been done by pre- 
 vious experimenters. He erected what he called a 
 geomagnetifer. It was merely a tall, resinous pole 
 planted in the earth, and carrying to its top a 
 galvanized iron rod, insulated from it by porcelain 
 knobs, and terminating in five pointed branches. 
 The electricity thus collected from the atmosphere 
 was carried to the soil and distributed by means of 
 a system of underground wires to the area of ground 
 to be electrically influenced. His first experiment 
 was with potatoes. The part of the field under 
 electric influence responded in a surprising man- 
 ner, as is evidenced by the following extract from 
 a newspaper report at the time : '" The eye is 
 arrested by a perceptible irregularity in the vegeta- 
 tion of the field. Within a circle limited exactly 
 by the place occupied in the earth by the conduct- 
 ing wires of atmospheric electricity, the potato 
 9 
 
 YE* 
 
 0** 
 
IO 
 
 plants possess a vigor double that of the plants 
 occupying the rest of the earth, and that, too, 
 without a gap, without a feeble point in this group 
 of superb stalks, sharply circumscribed as by a line 
 drawn by a compass." 
 
 According to the report of the committee dele- 
 gated by the Montbrison Society of Agriculture to 
 report on Paulin's experiments, a geomagnetifer 
 twenty-eight feet high, made its influence felt over 
 a radius of sixty-five feet, and the yield of potatoes 
 within this electrified area was from fifty per cent, 
 to seventy-five per cent, greater than without it. 
 This committee was quite enthusiastic over the re- 
 sults of Paulin's experiments, and awarded him a 
 special medal. He next experimented with his 
 geomagnetifer in a vineyard, and found that grapes 
 were much advanced in their growth, and that they 
 were sweeter (yielding about five per cent, more 
 sugar) and less acid. In further experiments he 
 found that spinach and celery were markedly influ- 
 enced, some leaves of the former reaching the length 
 of one and one fourth feet, and some stalks of the 
 latter three feet. Radishes and turnips were much 
 improved in size and quality, and sugar-beets 
 yielded a larger percentage of their saccharine 
 compound. It was also noticed that potatoes and 
 sugar-beets, electrically cultivated, were singularly 
 free from disease, while those outside of the influ- 
 ence were often seriously affected. 
 
 Spechnew modified Paulin's experiment by stick- 
 ing a number of poles into a field, each pole having 
 a point at its apex, and all being connected with a 
 
II 
 
 system of underground conducting wires, so as to 
 distribute the electricity to the soil. " By these 
 means," he says, " the electricity of the atmosphere 
 is rendered denser over the field, and the plants 
 develop in a field of high electric tension." After 
 five years of experimentation he was most favorably 
 impressed with the results. He tells us that 475 
 pounds of rye by the ordinary method of cultiva- 
 tion grew 2825 pounds of grain and 6175 pounds of 
 straw; while by the electric method the same quan- 
 tity of seed yielded 3625 pounds of grain and 9900 
 pounds of straw. Barley and wheat responded in 
 a similar manner, while oats yielded even larger 
 returns. 
 
 This method of applying electricity to vegetation 
 is a tempting one to pursue on account of the 
 abundance of atmospheric electricity at one's 
 command. 
 
 In speculating on cosmical electricity, Prof. Elihu 
 Thomson says: " The earth may possess the char- 
 acter of a huge conductor, the outer coating being 
 the rarefied conducting air, the inner coating the 
 ground and water surface, and the dielectric the 
 dense air between." The electric potential on 
 the top of the Eiffel Tower (984 feet high), he says, 
 may be as great as 10,000 volts; and if the increase 
 be 1000 volts for every 100 feet, on the average, it 
 would rise to 1,000,000 volts at an altitude of 
 twenty miles. So, we may liken the earth to a 
 huge Leyden jar, the dense air acting like the non- 
 conducting glass between the inner and outer 
 metallic coatings of the jar. Sometimes in charg- 
 
12 
 
 ing a Ley'den jar the electricity will break through 
 the glass (especially is it apt to do so if the glass 
 contains lead), and ruin the jar thereafter for ex- 
 perimental purposes. Likewise, sometimes, elec- 
 tricity, under such high potentials, in the upper, 
 rare atmosphere (in storm-clouds, for instance), will 
 break through the intervening denser air and dis- 
 charge itself into the ground or water this we call 
 a stroke of lightning. 
 
 Franklin raised his kite into such charged clouds, 
 and their electricity came down the string and filled 
 his Leyden jar, proving the identity of the elec- 
 tricity of the atmosphere with that of the plate 
 machines ordinarily used to charge Leyden jars. 
 
 What if Paulin's geomagnetifers could be made 
 to penetrate miles up into this reservoir of elec- 
 tricity and thus furnish an easy path for it to the 
 earth ? It is interesting to speculate upon the pos- 
 sibility of our being able to tap this great store- 
 house of stimulus to vegetation possibly even to 
 human development at will. 
 
 If we ask whence the outer, rare layers of our 
 atmosphere get their electricity, we may come 
 nearest a correct answer by saying from the sun, 
 that great source of so many forms of energy. We 
 know that displays of the aurora borealis, and also 
 electric storms, which are so unwelcome to tele- 
 graphers, are most frequent during the prevalence 
 of sun-spots, and we know that these spots are due 
 to some great disturbance upon the sun. Whether 
 the electricity thus generated upon the sun is carried 
 to' our upper atmosphere by minute particles thrown 
 
out by these eruptions, as is claimed by some, or 
 whether we get it by induction across space, as is 
 thought by others, we will not attempt to determine. 
 We do know, however, that the electric potential 
 does increase as we go up from the earth's surface. 
 According to Mr. McAddie, it can be measured 
 very accurately by means of his kite-experiment, 
 which bears some resemblance to Franklin's historic 
 one of so many years previous; there is, however, 
 a very marked difference between the conditions 
 which surrounded these two experimenters when 
 they sailed their kites into the skies. Franklin 
 courted the anger of the thunder-cloud and flew his 
 kite, with its pointed wire, into the face of death 
 so far as he knew. His theory of the identity of 
 electricity and lightning had not yet been proved 
 possibly it would be proved at the expense of its 
 originator's life; he knew that the electricity of the 
 Leyden jar was deadly to small animals, indeed his 
 own life had been shocked into insensibility by it. 
 
 The ingenious Mr. McAddie flew his kite into 
 the blue of a cloudless sky, and took note of the 
 sparks discharged from the lower end of the in- 
 sulated wire connected with it. By connecting an 
 electrometer with the wire, he could usually tell 
 whether the kite was rising or falling by reading 
 the larger or smaller deflections of the needle. 
 
 It may be of profit to consider, even if very 
 briefly, in closing this chapter, the effects of atmos- 
 pheric electricity upon man whether or not it 
 assists in his physical development and well-being. 
 Jean Paul Richter speaks of the value of the 
 
thunderstorm-bath, reminding us how " fresh, 
 cheerful, and elastic " we feel after a " warm or 
 tepid rain has penetrated to the skin," and how, 
 after being exposed to a thunderstorm and becom- 
 ing dry we are invigorated just as the flowers are 
 when they stand erect and look refreshed after the 
 passage of a storm. He says : " Why will they not 
 receive this united fire and water baptism from 
 above, and suffer themselves to be raised and 
 healed by the wonder-working arm in the thunder- 
 cloud ? ' ' He is practical when he advises a special 
 suit of clothes for the purpose, and the forming of 
 rain-parties when there is promise of wet weather 
 in the warmer seasons. If we incline to Richter's 
 belief, may we not reason that any form of dress 
 which insulates us in a high degree from the earth, 
 and thus prevents the passage of the atmospheric 
 electricity through our bodies, is detrimental to 
 us? 
 
 This may furnish one of the reasons why one 
 feels best when he is able to run barefooted; also 
 it may explain why in some parts of Germany it is 
 claimed that many diseases maybe cured by simply 
 connecting one's self with an iron rod driven into 
 the earth. Possibly we may refer any good which 
 may be derived from the numerous patent devices 
 for " electrolibrating," " polarizing," etc., to the 
 fact that they are merely contrivances for electric- 
 ally connecting one with the earth, and have 
 nothing inherent in themselves as a means of elec- 
 trically influencing the body. If there, perchance, 
 be any good in these high-priced and much-adver- 
 
tised devices, the author would recommend as 
 being just as efficacious (very possibly much more 
 so, and certainly much cheaper), the connecting 
 of one's ankles by means of an insulated wire with 
 gas or water mains, which have such good connec- 
 tion with the earth. 
 
 If, indeed, atmospheric electricity benefits plants, 
 as it certainly does, may it not be of use also to the 
 collection of living cells which go to make man's 
 body ? Possibly we think too lightly of this. 
 
CHAPTER III 
 
 ELECTRICITY FROM BATTERIES APPLIED TO 
 THE ROOTS OF PLANTS AND TO THE SUR- 
 ROUNDING SOIL 
 
 IN the previous chapters we dealt with frictional 
 or static electricity, that developed by plate- 
 electric machines or drawn from the upper atmos- 
 phere, and which possesses high electromotive 
 force but is very deficient in quantity a little 
 stream, as it were, moving under great pressure. 
 This, by reason of its great electromotive force, 
 can penetrate the badly conducting air to plants 
 and readily pass through them to the soil. Now 
 we shall consider the uses of galvanic electricity, 
 or that from batteries, and which, having low elec- 
 tromotive force, though capable of being delivered 
 in large quantities, cannot be applied advantage- 
 ously to the stalks of plants, but can be furnished 
 readily to the soil surrounding their roots. 
 
 A simple form of experimentation, which first 
 interested the writer and which yielded in the main 
 such favorable results that he was led to continue 
 his investigations, was as follows: 
 
 Two boxes of like size were filled with the same 
 kind of soil, and in each was planted the same num- 
 ber of hemp seeds at the same depth. They were 
 exposed to similar conditions of heat, light, and 
 16 
 
moisture. In the end of one of the boxes was in- 
 serted a thin piece of zinc, the height and breadth 
 of the box, and in the other end a piece of copper 
 of similar size. Both were pressed down almost to 
 the bottom of the box, and were connected above 
 ground by a copper wire soldered to their projec- 
 tions. Thus arranged the box was an earth-battery, 
 the like of which has been used for running clocks 
 and other machinery requiring but little current, 
 and also by previous experimenters in electro- 
 horticulture. The results were always in favor of 
 the seeds planted in the earth-battery, the plants 
 resulting from them being from twenty per cent, 
 to forty per cent, in advance of those in the box 
 without the zinc and copper. 
 
 Briefly, what goes on in the earth-battery is as 
 follows : some compounds in the moist, soil act 
 chemically upon the zinc (positive element), one of 
 the results of which is that a current of electricity 
 is generated; this passes through the soil to the 
 copper (negative element), up the copper to the 
 wire above the soil and through it to the zinc, 
 making a circuit. By inserting a sensitive galvano- 
 meter into this wire a current can be proved to be 
 flowing by the deflection of the needle. It is this 
 continuous current going through the soil which 
 acts upon some of the compounds in it, and also 
 upon the roots of the plants, giving us the good 
 results we generally obtain. Ordinary galvanic 
 cells, such as the " gravity," can be used to fur- 
 nish the current; all that is needed is to attach the 
 wire from the positive electrode of the battery to 
 
i8 
 
 a metallic plate driven into the earth, and the wire 
 from the negative to a similar plate at some dis- 
 tance from the other one. More current is fur- 
 nished, but the expense is much greater. 
 
 The earth-battery in the hands of Spechnew, in 
 the botanical gardens at Kew (London), achieved 
 some surprising results. He sank plates of zinc 
 and copper, about two feet square and connected 
 by copper wires, into beds in which he planted 
 various cereals and vegetables. He reported that 
 in some experiments with cereals in these electrified 
 beds the stalks were four times as large and the 
 yield of grain one and one half times as great as in 
 the beds not subjected to the electric treatment. 
 He produced in this electrified soil a radish seven- 
 teen inches long and five inches in diameter, and 
 a carrot nearly eleven inches in diameter and weigh- 
 ing five pounds. Both were juicy and fine-flavored. 
 Fischer, of Waldstein, experimented largely with 
 garden plants, placing his copper and zinc plates, 
 each sixty-five by forty centimetres, in the soil 
 thirty metres apart. In many plants he secured an 
 increase of from twofold to fourfold. He claimed 
 that the plants matured more quickly, and agreed 
 with Spechnew that they were always free from 
 disease, though often the surrounding plants were 
 badly affected with fungoid growths. 
 
 Professor Warner, of the Agricultural College of 
 Massachusetts, has verified at the Hatch Experi- 
 ment Station many of the results of the European 
 experimenters, and has given us some very interest- 
 ing ones of his own. In experimenting with let- 
 
tuce, he prepared two plots in a greenhouse so that 
 they would be subject to like conditions and influ- 
 ences. In the one he buried, at a little depth in 
 the soil, a system of copper wires consisting of 
 series of from four to nine strands one half inch 
 apart. He connected the wires with a battery of 
 two cells, which sent a continuous current of elec- 
 tricity through them. These plots were in a part 
 of the greenhouse which had been used for the 
 raising of lettuce, and in which great trouble had 
 been experienced from mildew. One of his ob- 
 jects was to see if the electric treatment would 
 have any effect upon the mildew. Equal numbers 
 of healthy lettuce plants, of the head variety, were 
 set in the plots; those in the plot with the electric 
 apparatus were planted over the wires so that their 
 roots could come in contact with them. He re- 
 ported that five plants out of fifteen in the electric 
 plot were killed by the mildew, the other ten being 
 " well developed and the heads large." In the 
 corresponding unelectrified plot " only three plants 
 had partially developed, and two of them were 
 nearly destroyed by the mildew only one was free 
 from disease." It was noticed that when the cur- 
 rent became weak, or was interrupted, the heads 
 began to feel the destructive influence of the mil- 
 dew; also that the largest heads were over the 
 greatest number of wires and nearest where the 
 wires were attached to the battery. A strange 
 sight presented itself on examining the roots: it 
 was found that they had " grown about the wires 
 as if there they had found the greatest amount of 
 
2O 
 
 nourishment." Professor Warner sums up by say- 
 ing, " everything considered, the results were in 
 favor of electricity. Those plants subjected to the 
 greatest electrical influence were hardier, healthier, 
 larger, and had a better color, and were much less 
 affected by mildew than others." In later experi- 
 ments he found that parsnips, salsify, radishes, and 
 peas thrived especially well under the electric 
 treatment, while turnips and beets responded to a 
 less degree. 
 
 Spechnew, having obtained such excellent re- 
 sults from the use of earth-batteries, was led to 
 perform the experiment of electrifying seeds before 
 planting them, to see if the current would have any 
 effect to make them develop sooner. He put some 
 seeds into water until they swelled, and then trans- 
 ferred them to a glass cylinder, pressing copper 
 discs against them at both ends. The disks were 
 connected with the poles of an induction coil, and 
 the faradic current applied to them for a minute 
 or two. Immediately afterwards they were planted. 
 Peas, beans, barley, and sunflowers developed in 
 about half the time required for those not so treated, 
 and the resulting plants were healthier looking, 
 with larger leaves and brighter colors; the yield, 
 however, was not increased. 
 
 The results reported by other experimenters cor- 
 respond so closely with those detailed in this chap- 
 ter that we need not give space to them. 
 
 The small expenditure connected with this line 
 of experimentation in electro-horticulture should 
 make it popular. 
 
CHAPTER IV 
 
 EFFECTS OF THE ELECTRIC LIGHT UPON 
 VEGETATION 
 
 IT is well known that if a plant be kept in a dark 
 place it will lose its green color and pine away. 
 Experimenting with plants deprived of sunlight, 
 Professor C. W. Siemens found that if he substi- 
 tuted the light furnished by electricity, the plants 
 would keep in a large measure their green color 
 and grow almost as vigorously as with the sun 
 shining upon them. 
 
 Recently a gardener, without any scientific abil- 
 ity, and without even the intention of experiment- 
 ing, arrived at a similar conclusion. He was 
 extremely puzzled one day to find that some 
 lettuce plants at one end of his greenhouse were 
 far in advance of those of the same age and variety 
 at the other end. He was finally led to conclude 
 that an arc-electric lamp, which had been burning 
 every night at the prolific end of the lettuce bed, 
 was the cause of his good fortune; and further ex- 
 perimentation proved his conclusion to be correct. 
 
 The arc-electric lamp furnishes a light very 
 similar to sunlight, being, however, somewhat 
 richer in the rays beyond the violet and slightly 
 21 
 
22 
 
 deficient in the orange rays. The use of an orange- 
 colored globe makes it more nearly like sunlight, 
 and favors its action upon vegetation. The naked 
 arc-light, if too near some plants, exerts a detri- 
 mental action upon them, and one must carefully 
 study the susceptibility of the individual plant in 
 order to regulate the distance between it and the 
 light. The length of time the lamp is kept burn- 
 ing and the color of the shade through which the 
 light is permitted to pass are also matters of im- 
 portance. 
 
 The value of interposing glass between the light 
 and the plants has been demonstrated frequently: 
 for instance, Dr. Bailey, of Cornell, whose work in 
 electro-horticulture has been of the highest order, 
 found that radishes under the naked light lost from 
 forty-five per cent, to sixty-five per cent. ; under a 
 light covered by an opal globe the loss was but 
 slight, while when the light was strained through 
 the opal globe and the glass roof of the greenhouse 
 there was an increase in both tubers and tops. He 
 obtained similar results with beets and spinach. 
 Cauliflowers were so influenced by the light as to 
 grow tall and extend their leaves in a vertical 
 direction, but they did not head so well as those 
 grown without the light. Tulips and petunias 
 grew taller and more slender, had richer hues, and 
 bloomed earlier and more freely. Lettuce was 
 from ten to twelve days earlier, and felt the influ- 
 ence of the light all over the greenhouse, which 
 extended forty feet from the lamp. Another ex- 
 perimenter tells us that a 2Ooo-candle-power arc- 
 
lamp will markedly influence a bed of lettuce sixty 
 feet square. 
 
 Siemens found that the electric light was effica- 
 cious in producing chlorophyll in the leaves of 
 plants; that it promoted the growth of the whole 
 plant ; and also hastened the development of 
 flowers and fruit, giving to the former more intense 
 coloring, and to the latter finer flavor. In straw- 
 berries the rich red color and fine flavor were 
 especially noticeable, and the berries were brought 
 to ripeness two weeks before the usual time. Mel- 
 ons, also, were quite responsive to the light, and 
 were much improved in aroma. 
 
 In experimenting with the electric light one will 
 find it very interesting to study its effects upon 
 plants at different distances, as well as the effects 
 of different transparent substances placed between 
 it and the plants. Some plants are apparently 
 scorched by the light, even if not near enough to 
 feel the effects of its heat. The ultra-violet rays, 
 which seem to cause this, are largely absorbed by 
 plain glass. When a part of a plant is shielded 
 from the light by a piece of ordinary glass one 
 may sometimes see a distinct line of demarkation 
 between the part so protected and that exposed to 
 the glare of the light; even a single leaf may be 
 partly scorched and partly of an intenser green as 
 a result of its position in this respect. 
 
 But one must find the length of time each plant 
 prefers the light to profit most by its influence, in 
 addition to ascertaining its preference for intensity 
 and for the color of the glass surrounding it. 
 
Plants seem to have an individuality, and often 
 show a decided liking for certain regulations in the 
 use of the light in order to do their best when sub- 
 jected to its influence. 
 
 One would think that plants need the darkness 
 for their well-being, just as animals require the 
 night for sleep and refreshment; but this has been 
 declared by a prominent investigator not to be the 
 case, or at least but to a very limited extent. 
 Under the stimulus of the electric light they keep 
 on growing at night almost as thriftily as in the day- 
 light. What to us would be dissipation and end in 
 disease, seems to them to be profitable pleasure, if 
 the light is properly regulated. Mr. B. F. Thwaite 
 tells us that the leaves of that beautiful plant, the 
 acacia cophanta, which close at night, open almost 
 magically when removed from the darkness into the 
 brilliant beams of the arc-lamp; the leaves nearest 
 the root being the first to be influenced. 
 
 We have been alluding to the effects of the 
 steadily shining arc-light upon vegetation; but if 
 it is flashed at short intervals upon plants it seems to 
 have increased power, at least it will draw the plants 
 more rapidly and strongly toward itself. They 
 seem to be whipped up, as it were, by the violent 
 alternations of intense light and darkness. Helio- 
 tropism is the name given to this effect; it deserves 
 a fuller investigation. 
 
 It is not unlikely that in future experiments, 
 devices will be used to graphically record the 
 progress of the growth of plants. By using the 
 method of M. Mach, one may see plants grow, and 
 
2* 
 
 be able to follow them in some of their trans- 
 formations. 
 
 His process consists, first, in photographing 
 growing plants at suitable intervals, and, secondly, 
 by means of a somewhat complicated apparatus, in 
 passing rapidly before the eye the photographs of 
 the plants in their various stages of growth. Thus, 
 in a space counted by seconds, we may have passed 
 before our wondering eyes the birth, developing, 
 flowering, fruiting, and death of a plant. By re- 
 versing the order of the photographs we are amazed 
 to see the fruit evanesce into the flower, the flower 
 contract into the bud, the bud absorb into the stem, 
 and finally the stem disappear into the ground. 
 
 By attaching a piece of fine platinum wire to a 
 growing plant, and fastening a small piece of crayon 
 to the other end of the wire, it is said that we may 
 have recorded on a rotating drum, covered with 
 white paper, tracings showing its growth. If we 
 cover the drum with narrow strips of platinum foil, 
 and connect them with one pole of a galvanic bat- 
 tery, and the wire attached to the plant with the 
 other, and then place an electric bell in the circuit, 
 we will hear, as the drum rotates, the ringing of the 
 bell when the wire presses upon the foil, and have 
 silence when the wire presses upon the spaces be- 
 tween the strips of foil. As plants are said to grow 
 most rapidly between the hours of four and six in the 
 morning, if we make the strips sufficiently narrow, 
 or have a rapidly growing plant, we will have the 
 bell rung quite frequently at our waking hour. 
 
CHAPTER V 
 
 HOW DOES ELECTRICITY ACT UPON VEGE- 
 TATION? 
 
 BEFORE speculating concerning the rationale 
 of the action of electricity upon the growth 
 of plants, it may be helpful to review, even very 
 briefly, the manner in which plants get their nutri- 
 tion from the air and soil. 
 
 The atmosphere is a mixture of one fifth oxygen 
 and four fifths nitrogen, with varying percentages 
 of carbon dioxid and vapor of water, besides 
 minute quantities of a few other compounds. The 
 leaves of plants have the power of breaking up the 
 carbon dioxid (CO 2 ) and fixing its carbon, at 
 the same time setting free its oxygen. This disin- 
 tegrating action upon the carbon dioxid in wood- 
 lands is performed on such a large scale that suffi- 
 cient oxygen is liberated to produce the exhilirating 
 feeling one often experiences during an outing in 
 the woods. This appropriation of carbon from 
 carbon dioxid goes on when two conditions co- 
 exist : sunlight and the presence of chlorophyll in 
 the leaves. To properly appreciate the value of 
 sunlight to vegetation one must realize that it not 
 only enables the chlorophyll to decompose carbon 
 26 
 
dioxid, but also that it is the stimulus which em- 
 powers vegetation to make chlorophyll, the con- 
 stituent to which plants owe their various hues of 
 green. It is well known that a period of rainy 
 weather, with the absence of sunlight, diminishes 
 very much the quantity of chlorophyll in plants; 
 also that in dark cellars they lose it entirely, and, 
 as a consequence, their lives, though an abundance 
 of carbon dioxid be present. 
 
 From the soil plants get most of their water, and 
 nearly all of their nitrogen (so very important to 
 their well-being), besides the various salts of pot- 
 ash, lime, etc., which they require. Most of these 
 substances exist in the soil in forms which can be 
 absorbed readily by the roots; this is not the case, 
 however, with nitrogen, so we offer a few words 
 concerning it. 
 
 Nitrogen is an inert gas, colorless, odorless, and 
 tasteless; it will neither burn nor support combus- 
 tion, and yet it is indispensable to life not only in 
 plants but in human beings. Although it is so 
 abundant in the air (simply mixed with oxygen), 
 neither plants nor human beings are able to appro- 
 priate it directly from the atmosphere. It seems nec- 
 essary that it first should be made into compounds 
 before plants can utilize it. These compounds 
 are generally formed by oxygen and hydrogen unit- 
 ing with it under certain conditions: nitrous acid 
 (HNO 2 ) and nitric acid (HNO 3 ) are examples. 
 Usually compounds of nitrogen are produced by 
 the decomposition of organic matter by ferments; 
 thus prepared they are taken up readily by plants 
 
28 
 
 and made a part of them. However, the roots of 
 some plants, under rare conditions, seem able to 
 appropriate directly the nitrogen brought to them 
 in the air which has been absorbed by rain-water. 
 Legumenous plants are fortunate in this respect; 
 an example will be given later. 
 
 Concerning the manner in which the electric 
 light helps plants to grow, experimenters have 
 given us some valuable information; but in rela- 
 tion to the action of the current itself upon vegeta- 
 tion much needs to be learned and here is an 
 inviting field for the microscopist as well as for 
 the chemist. 
 
 The light furnished by electricity acts upon 
 plants in a manner very similar to sunlight. It 
 stimulates the formation of chlorophyll and assists 
 in the decomposition of carbon dioxid, upon which 
 plants feed so largely. That it helps in the forma- 
 tion of starch in the leaves can be proved in a very 
 interesting manner. Keep a plant in darkness for 
 several days so that the starch may disappear from 
 its leaves. Then cover one of its leaves with a 
 piece of tinfoil, and cut a letter or figure through 
 the foil without injuring the leaf. Expose the leaf 
 to the electric light, which will stimulate the pro- 
 duction of starch in the part of the leaf which it 
 reaches through the perforations in the tinfoil. 
 After a couple of days pluck the leaf and at once 
 put it into boiling water (to render the starch solu- 
 ble), and then into alcohol (to dissolve out the 
 chlorophyll). The leaf will now be colorless, but 
 will contain dissolved starch in the parts which 
 
were exposed to the electric light. To render this 
 visible, immerse the leaf in a weak solution of 
 iodin, and the letter or figure will stand out in a 
 blue color. 
 
 In considering the action of atmospheric elec- 
 tricity upon vegetation, we have to deal with a 
 stimulus which exists in abundance. Plants grow 
 most vigorously where it is most abundant, and 
 with greatest rapidity in the early morning when 
 the dew is more plentifully upon them, making 
 them better conductors. Its most important action 
 upon the stalks of plants is that of increasing their 
 circulation of sap. 
 
 Discharges of electricity in the air, especially 
 during thunder-storms, cause some union between 
 the oxygen and nitrogen in the vicinity of the dis- 
 charges, forming oxides of nitrogen, which, being 
 soluble in water, are carried to the roots of plants 
 and absorbed by them directly. 
 
 Electricity passed through the soil by earth-bat- 
 teries, the geomagnetifer, or other means, has some 
 action upon its chemical constituents. We are 
 familiar with the effects of a current of electricity 
 upon water (OH 2 ) when the electrodes of a battery 
 are placed in it: from each molecule of water two 
 atoms of hydrogen go to the negative electrode 
 and one atom of oxygen to the positive. Since the 
 time when Davy decomposed the alkalies, soda and 
 potash, by means of electricity, nearly every com- 
 pound has yielded to this mysterious power, which, 
 as it were, shakes their molecules until the atoms 
 composing them fly apart. In like manner cur- 
 
rents of electricity may break up the more complex 
 compounds in the soil into simpler ones, upon 
 which the roots of plants can feed. 
 
 Spechnew found that one hundred pounds of 
 earth, subjected to the electric current for a certain 
 length of time, contained one ounce of soluble 
 material, while a similar quantity of the same kind 
 of earth not so treated contained but half an ounce. 
 
 Some observers believe that electricity decom- 
 poses the constituents of the soil much as quick- 
 lime does, and it is largely on this account that 
 plants are more richly fed in electrified earth. 
 Others think that, in some manner, under the elec- 
 tric influence, nitrogen from the air combines with 
 some other substances in the soil, making com- 
 pounds which are readily absorbed by roots of 
 plants. A recent experimenter claims that the 
 particles of electrified earth are set into molecular 
 vibration, thus loosening the earth. Faraday, in 
 his researches many years ago, declared that plants 
 requiring much nitrogen for their development 
 would be benefited by being grown in electrified 
 earth. 
 
 Let us consider how uncombined nitrogen in the 
 soil, carried there by the water, may be given to 
 the roots of plants without first being formed into 
 compounds. We will state the case of one of the 
 legumenous plants, which plants find nitrogen so 
 very necessary to their existence. It is well known 
 that many of the legumes can sustain themselves in 
 soils too poor in nitrogenous compounds to support 
 other plants. They seem to do so by feeding 
 
directly upon the nitrogen brought to them from 
 the air by rain-water, and this by the aid of certain 
 bacteria at their roots. On the roots of the pea, 
 for instance, we often find numerous tubercles; 
 these used to be thought to be evidence of disease, 
 and the microscope seemed to corroborate this by 
 showing them to be filled with micro-organisms 
 (bacterium radicicolus). However, it was soon as- 
 certained that instead of causing harm to the pea 
 plants these colonies of bacteria contributed very 
 largely to their welfare. They actually fed the 
 plants with nitrogen through their roots. If peas 
 are planted in a soil which has been washed and 
 calcined to deprive it of its nitrogenous com- 
 pounds, they will soon become sickly and die; but 
 if some water is made muddy with a little soil in 
 which healthy peas are growing, and soaked to 
 their roots, they become healthy and thereafter 
 flourish. The water carries to their roots some of 
 the bacteria from the ground in which the healthy 
 peas are growing. These micro-organisms attach 
 themselves to the roots, and while living, in a 
 measure, upon the nutrition in them, more than 
 pay for what they eat by giving to the plants 
 through their roots quantities of nitrogen, taken in 
 some mysterious manner from the air brought to 
 the soil by the water. Let us wonder if electricity 
 may not help in this matter by stimulating the 
 activity of these bacteria, for it is said to favor 
 very much the growth of peas when applied to the 
 soil. Before directing our attention to the question 
 of the action of electricity upon bacteria, let us 
 
notice the offices of some other bacteria in the 
 soil. 
 
 Organic matter containing nitrogen, such as 
 manure, is converted by fermentation into ammo- 
 niacal compounds. By one kind of micro-organ- 
 isms in the soil these compounds are oxidized into 
 nitrites, and by another kind the nitrites are raised 
 to nitrates, 1 ready for absorption by the roots of 
 plants. Both organisms are found in all good soils; 
 in the future farmers may sow them in bad soils, 
 not forgetting to sow with them some phosphates, 
 sulphates, etc., as foods for the micro-organisms 
 themselves. 
 
 Here, as very frequently elsewhere, man is de- 
 pendent upon bacteria for some of the good things 
 in life. In these days of antisepsis, when the tend- 
 ency is to sterilize everything, especially our foods, 
 it may soften our animosity towards the disease- 
 producing micro-organisms to reflect that there are 
 many of their kin which are friendly to us : the 
 delicate flavors given to butter and to cheese are the 
 results of their action ; even the process of digestion 
 is probaby dependent in a manner upon them. 
 
 But what has electricity to do with the action 
 
 1 When we consider how scarce and costly nitrates are, we 
 can rightly value the work of these two kinds of bacteria. 
 They make the nitre beds of Chili and India by converting 
 the organic matter deposited there by fish-feeding sea-birds 
 into nitrates of soda and potash. The absence of rain in these 
 localities causes the nitrates to effloresce upon the dry soil, 
 from which they are easily collected ; in other places they are 
 washed away on account of their great solubility in water. 
 
33 
 
 of bacteria in feeding atmospheric nitrogen to 
 the roots of plants ? and what with their action in 
 decomposing ammoniacal salts finally into sol- 
 uble nitrates, ready for absorption by the plants ? 
 Does electricity stimulate the functions of the 
 bacteria ? 
 
 A current of electricity passed through water 
 containing certain freely floating organisms causes 
 them to take notice of the fact and accommodate 
 themselves to it. Dr. Waller has shown that a 
 vessel of water with parameciae plentifully inhabit- 
 ing it is curiously affected if a current of electricity 
 is passed through it. The minute organisms at 
 once form in line and rush towards the negative 
 electrode, and if the current is reversed hasten the 
 other way. One might think that the current 
 drives the minute organisms with it, as it does 
 some chemicals in cataphoresis; but, strange to say, 
 other micro-organisms swim, as it were, against the 
 current. D'Arsonville insists that electricity of 
 high potential has a definite effect upon micro- 
 organisms, and his remarkable experiment with the 
 bacillus pyocyaneus, which caused it to change the 
 color of its secretive pigment, is much in evidence. 
 And then we know of the stimulating influence of 
 thunderstorms upon fermentative germs; for in- 
 stance, upon the lactic ferment, causing it to turn 
 milk sour more quickly. 
 
 We think we have sufficient knowledge of the 
 effects of electricity upon the cells of complex man 
 to warrant us in believing that it does favor their 
 nutrition; why not infer that it has a like action 
 
34 
 
 upon the cells ' of plants, and, also, upon the func- 
 tions of the bacteria concerned in feeding nitrogen 
 to plants ? 
 
 In these early days of the X-rays of Roentgen, 
 let us wonder what effect they may have, not only 
 on plants above the soil, but especially on the roots 
 and bacteria in the soil, which soil the rays can 
 penetrate to a considerable depth. 
 
 So far experiments have not been conclusive. 
 Professor Atkinson states that while plantTtissues 
 absorb the Roentgen rays quite freely, there is no 
 marked influence on the growing parts, and, also, 
 that bacteria are negatively affected. Other ex- 
 perimenters report that exposure of the bacillus 
 prodigiosus to the radiations of an X-ray focus-tube 
 induces very marked increase of growth and pecu- 
 liar changes in the pigment-forming powers of this 
 particular micro-organism. Similar changes were 
 noted in some of the lower forms of vegetable life, 
 notably in the protococcus. 
 
 1 Stanoievitch, a Russian scientist, has made the interesting 
 observation that the markings produced by growth on a sec- 
 tion of wood or vegetable, are very similar to those produced 
 by sifting iron filings upon a plate of glass and holding the 
 poles of a magnet directly under it. And he argues that there 
 is an analogy between the actions of plants which arrange 
 their cells in such definite positions, and the play of the magnet 
 which makes the familiar " lines of force." 
 
CHAPTER VI 
 
 SOME SUGGESTIONS AND A GLIMPSE OF AN 
 ELECTRIC FARM OF THE FUTURE 
 
 THE simplest and cheapest method of getting 
 electricity into the soil and to the roots of 
 plants is by the use of some form of the geomag- 
 netifer. In using this device we must be careful to 
 arrange it so that the atmospheric electricity will 
 come down the wire on the pole to the system of 
 wires in the soil, and not down the pole itself to the 
 earth immediately surrounding it. The pole may 
 be made a non-conductor by being coated with 
 resin, or it may be set into a non-conducting sub- 
 stance. As to the height of the pole, it should 
 reach far above the surrounding trees or other high 
 objects, or, better, the pole should be situated on 
 elevated plots of ground. We must learn more 
 about the relation of the area of soil beneficially 
 affected to the height of the pole. We also must try 
 to find out more about the nature of the soils most 
 responsive to the application of electricity, as well 
 as the varieties of plants most susceptible to its 
 influence. 
 
 After the installation of a geomagnetifer, the 
 main cost will come from the replacing of the dis- 
 35 
 
tributing wires in the ground, which wires are sub- 
 ject to corrosion. 
 
 The use of earth-batteries seems to be a more 
 reliable method of furnishing electricity to the soil. 
 For their successful use the soil should be kept 
 fairly moist, especially around the metallic plates. 
 The use of weak acids in the vicinity of the zinc 
 plates may be of advantage if of any disadvant- 
 age, it would be that they consumed the zinc too 
 rapidly, thus increasing the expense, possibly with- 
 out a corresponding increase in the good done to 
 the crop. The plates should be of ample size, and 
 their distance apart should be regulated to suit the 
 crops planted between them; the greater the dis- 
 tance the larger the resistance to the current and 
 the less its strength. When a current of but little 
 strength is wanted by soils or plants sensitive to it, 
 rows of zinc plates should be connected with rows 
 of copper plates at considerable distances from 
 each other. If stronger currents are needed, the 
 distance should be diminished. A sensitive gal- 
 vanometer inserted in the wire above the ground 
 will be of assistance in finding out the strength of 
 current best suited to the circumstances of soil and 
 crop; it will surely tell us whether or not a current 
 is flowing through the soil: this will point out the 
 cause of occasional failures in this form of experi- 
 mentation. The action of the battery will slowly 
 destroy the zinc, while the copper will last almost 
 indefinitely; so it will be best to raise the zinc 
 plates from the soil when no crop is being grown, 
 or, at least, to disconnect the wires which join the 
 
37 
 
 zinc and copper plates. Iron can be used instead 
 of the more expensive zinc, but the current fur- 
 nished by the iron and copper battery is almost too 
 weak to be of any service. 
 
 The advantages of this method over that in which 
 the geomagnetifer is used are the absence of under- 
 ground wires which corrode and have to be replaced 
 in time, and the power to furnish a more constant 
 supply of current. The one disadvantage is the 
 interference the plates and wires offer to cultivation. 
 
 The earth-battery would seem to be the more use- 
 ful in raising berries and vegetables in greenhouses 
 or small plots, and the geomagnetifer in growing 
 potatoes or cereals in fields. 
 
 When electricity can be generated cheaply enough 
 by dynamos or other means, its application to soils 
 in which crops are growing can be regulated to suit 
 every condition ; each soil and crop will get its dose 
 as exactly and as effectively as the physician pre- 
 scribes tonics and nutrients possibly more so. 
 
 In using the arc-light the main things to be con- 
 sidered are the proximity of the plants to it, the 
 nature and color of the shade interposed between 
 it and the plants, the length of time the plants are 
 exposed to its rays, and the hours of the day or 
 night most suitable for its use. 
 
 If the arc-light is too near the plant, though not 
 near enough to affect it by its heat, it may, never- 
 theless, scorch its leaves and cause serious damage. 
 The ultra-violet rays are said to be responsible for 
 this, as they, according to Professor Rowlee, " pro- 
 duce great activity in the protoplasmic contents of 
 
the cells, particularly of the palisade tissue, or 
 hasten the physiological process. This activity 
 calls at once for large supplies of water, and it is 
 drawn first from the overlying epidermal cells; 
 these cells being emptied of their contents, collapse 
 like an empty grain bag. In other words, the vital 
 activity is hastened so much by the naked light 
 that the plant cannot supply materials quickly 
 enough, and it is forced to death." 
 
 Plain glass will strain out these dangerous ultra- 
 violet rays sufficiently to prevent this damage, or 
 it may be avoided by removing the lamp to a suffi- 
 cient distance from the plants. 
 
 Experiments are being conducted which may de- 
 termine for us just what colors of lamp-shades are 
 the most desirable for use in cultivating the various 
 plants which are benefited by the arc-light. Ex- 
 periments have been made with the spectrum of the 
 sun to find out which of its rays are efficacious in 
 causing the formation of woody fibre, which in the 
 formation of starch, which in the formation of 
 chlorophyll, etc., but the results have not been 
 conclusive on account of the difficulty of maintain- 
 ing the spectrum steadily at the same place, and on 
 account of the short periods of time it could be 
 depended upon for action. But with the arc-light 
 the spectrum can be furnished continuously, and 
 its different colors kept upon a number of similar 
 plants as long as desired. Thus we may learn 
 which colors are best suited to the varying needs 
 of plants at the different stages of their growth. 
 Here again we may meet the question of dosage, 
 
39 
 
 and may prescribe certain rays for early life, others 
 for adult, or combinations for specially developing 
 the starchy, saccharine, woody, or other substances 
 in the plants; or we may hasten or retard the 
 ripening of crops to suit the varying conditions of 
 the market. 
 
 While it is stated by careful investigators that 
 plants do not seem to need rest at night, yet further 
 study of them under the influence of the electric 
 light may put us in possession of facts which will 
 enable us to give them their light-stimulus at the 
 proper times and for the exact length of time, in 
 addition to giving it of the right strength and color. 
 The fact that diastase, which transforms starch into 
 sugar, acts best in the absence of light, seems to 
 argue that the leaves of plants, which make starch 
 in the presence of light, should have periods of 
 darkness to permit this transformation to go on 
 satisfactorily; otherwise the leaves may become 
 choked with starch, and the plant, although it has 
 an abundance of starchy food, suffer because it 
 cannot utilize it in the presence of continuous light. 
 Some observers warn us not to give the light too 
 freely at noonday, or when the heat is greatest, 
 and others suggest that alternations in the dosage 
 are of value; we have before made mention of the 
 effects of heliotropism. 
 
 When one thinks of the combinations which can 
 be made of the methods of furnishing electricity to 
 the soil and to plants with the methods of furnishing 
 electric light to the leaves of plants, he feels how 
 little indeed has been accomplished, and sees ahead 
 
work for years of experimentation. And then there 
 is the possibility that plants, in future generations, 
 may become accustomed to being partly fed by the 
 electric light, and partly by currents in the soil, and 
 may adapt themselves to the new conditions to the 
 increased profit of the horticulturist. 
 
 While the vast majority of the experimenters have 
 reported results highly favorable to electro-horticul- 
 ture, yet, as we have before pointed out, there have 
 been a few who did not obtain the good results so 
 enthusiastically heralded by others; it may be that 
 in some localities of the earth's surface certain con- 
 ditions obtain which render such places more favor- 
 able ones for such experimentation than others. 
 
 Experiments with earth-batteries may fail on ac- 
 count of the connecting wires above ground being 
 twisted around the projecting plates instead of being 
 soldered to them. In dealing with such feeble 
 currents, no more resistance should be opposed to 
 them than is absolutely necessary. And then the 
 soil may be unsuitable for sufficient chemical action 
 upon the zinc plate; possibly too scanty in proper 
 mineral matter, or too. dry, and hence unable to 
 generate a useful current. It is always well to test 
 the strength of the battery, and still more import- 
 ant to see if there is any current flowing, by means 
 of a sensitive galvanometer inserted in the wire 
 connecting the plates. 
 
 The practical farmer will want to know if electric 
 farming will increase his profits before he thinks 
 seriously of adopting it. He may agree that it will 
 be more scientific, perhaps more interesting, and 
 
likely less laborious, but will it pay ? It is too 
 early to give satisfactory figures concerning the 
 results of the application of electricity to the grow- 
 ing of plants and vegetables, as experiments have 
 not yet been made on a sufficiently large scale to 
 furnish reliable statistics; but the smaller experi- 
 menters seem much encouraged, and some of them 
 are now engaging in electro-horticulture much more 
 extensively. 
 
 As regards the use of electricity as a motive 
 power on the farm, the experiments have reached 
 the stage where figures can be safely given in its 
 favor. Recently Julius Muth, United States Con- 
 sul in Mecklenburg, Germany, gives some interest- 
 ing figures concerning a farm near that place run 
 entirely by electricity. The dynamo furnishing 
 the current is driven by a turbine whose power is 
 furnished by a small brook, and the electricity is 
 stored up in an accumulator of sixty-six large cells. 
 The yearly expenses of running the farm under the 
 old system were $1713.60, while under the elec- 
 tric system they were reduced to $1492. 
 
 Although it was not our intention to consider the 
 application of electricity to the machinery of the 
 farm in this little book, yet we give room to a state- 
 ment of Otto Doederlein, United States Consul at 
 Leipsic, in his report to the Department of State, 
 in 1895, concerning " The Electric Plow in Ger- 
 many." He says, after giving elaborate figures: 
 " It is thus evident that the working expenses of 
 the electric plow for extensive husbandry amount 
 to less than half of those incurred in working the - 
 
steam plow. This contrast is readily explained, 
 for (i) the capital sunk in plant is only one third 
 of that required for the steam plow; (2) the ex- 
 penses connected with the generating of power are 
 materially lower than is the case with the steam 
 plow, in which a very considerable surplus power 
 has to be raised in order to work the pulleys and 
 brakes and to overcome the stiffness of the rope; 
 (3) the expensive transport of water is herein en- 
 tirely done away with." His reference is to the 
 Electric Tilting Plow, made by Messrs. Zimmer- 
 mann & Co. He also adds, " I have been in- 
 formed by the director of the Haale factory that 
 electricity will shortly also be used in digging out 
 potatoes and sugar-beets." 
 
 When electricity can be furnished more cheaply 
 than at present, what may not a combination of 
 electric farm machinery, electric culture of the 
 soil, and electric stimulation of plant-life mean to 
 the farm ? 
 
 The following extract from a lecture delivered 
 by the writer some years ago at a Farmers' En- 
 campment is appended, thinking a little electric 
 speculation may interest some of the readers: 
 
 " The farmer we see in the future has no need of 
 horses. Occasionally he may be found with a pair 
 of spirited animals, with which to vary the monotony 
 of riding in his speedy electric carriage. His work 
 is done by electricity furnished by some near-by 
 waterfall, or by a combination of wind-engine and 
 storage-battery, or by some company which manu- 
 factures electricity cheaply and sells it to communi- 
 
43 
 
 ties of farmers. His produce is sent to the nearest 
 shipping station by means of electric railways on 
 the highways, which run alike winter and summer, 
 and which, when once put down, require no filling 
 up of chuck-holes and no plowing up of the sides 
 of the roadway and throwing of the dirt into the 
 centre. Scattered over his farm are numerous poles 
 carrying insulated wires. Let us go out to his wheat- 
 field and see what he is doing. It is the time of 
 harvest. We see an odd-looking reaper and binder ; 
 from it, as it moves rapidly along, there pays out 
 some insulated wire which connects the reaper with 
 the wire coming to the field from the highway, 
 through which wire it receives the energy which 
 runs it. Thus the farmer with great rapidity cuts, 
 binds, and shocks his wheat; he does the work 
 alone and complains not of weariness, but only of 
 a sense of loneliness. As he stops his machine for 
 a few moments to shift the wire, he tells us that this 
 method is getting too slow for him, on account of 
 the reeling and unreeling of the wire, and that he 
 is thinking of buying the latest patent which carries 
 its own electric supply in storage-batteries, only he 
 fears that the recent experiments looking toward 
 making electricity directly from coal are so near to 
 success that this new machine, in turn, will soon 
 become old-fashioned. 
 
 " After he is done a wagon comes out, moved by 
 the same mysterious force, and gathering the 
 sheaves, takes them to the barn. In course of time 
 an electric thresher, which cannot set the barn on 
 fire from red-hot cinders, separates and cleans the 
 wheat; and soon the electric railway transports it 
 to the market. 
 
 " His electric plow is quite an improvement on 
 the one which not long ago turned up the first fur- 
 row in American soil at the Kansas sorghum experi- 
 ment station, and his electric harrow pulverizes the 
 ground to an evenness that is marvellous. . ... 
 
44 
 
 Among the many lesser inventions of which he 
 makes use, we notice a simple device to protect 
 some favorite trees from the invasion of caterpillars. 
 The trunks of the trees have two narrow bands of 
 copper around them at short distances apart. 
 These bands are connected by wires with the poles 
 of a battery capable of delivering a very strong 
 current. When a caterpillar crawls up one of these 
 trees and crosses the metallic bands, it is in the 
 same unpleasant situation as the murderer in the 
 4 electrocution chair ' at Sing Sing. Its body 
 makes the connection between the terminals of the 
 battery, and it goes no farther. If the current is 
 powerful enough a diminutive arc-light is the result, 
 and a cinder all that is left of the caterpillar. In- 
 deed he is tempted to use this method, with some 
 modifications, in dealing with the chicken thief, 
 the burglar, and even the ubiquitous tramp. 
 
 " See the huge earth-batteries and tall geomag- 
 netifers he uses in forcing his crops ; how he spreads 
 electricity, as it were, through the soil, and keeps 
 large arc-lamps burning at night to still further 
 assist in hastening the growth of his farm products. 
 With the heat generated by these lamps, or by 
 means of special resistance coils, generating it more 
 abundantly, he is able to prevent frosts doing 
 damage to his earlier and more tender fruits and 
 vegetables. 
 
 "Had the late rain-producing experiments been 
 successful, we might even picture this fortunate 
 farmer calling down the refreshing showers when- 
 ever he thought his crops needed them. And if he 
 believed, with Jean Paul Richter, that the thunder- 
 storm-bath was as refreshing and invigorating to 
 the human system as to the trees and flowers, he 
 would invoke the storm with his bombs when he 
 thought his grain needed rain, regardless of the fact 
 that there was a picnic in the wood or a farmers' 
 encampment in the grove indeed, he would take 
 
45 
 
 out his wife and children and form a ' rain-party,' 
 and be invigorated and strengthened by the 
 'wonder-working arm of the thunder-cloud.' 
 
 " Our electric farmer, besides using electricity 
 to assist in maturing his crops, has learned how to 
 apply it to the destruction of one of his greatest 
 enemies weeds. With a dynamo furnishing a cur- 
 rent stepping up from 2000 to 24,000 volts, as 
 needed, he sends the current through the weeds by 
 means Of brushes of fine wire passing among their 
 tops as his generator moves over the field, the 
 other pole of the circuit being connected with the 
 ground through the wheels of the machine carrying 
 the dynamo. This strong current breaks up the 
 cellular tissues of the weeds and thus destroys them 
 just as, on a larger scale, a stroke of lightning 
 destroys a tree. ... In picturing the electric 
 farm one has a very large range of probabilities to 
 draw upon, but there is ever the danger of his let- 
 ting his fancy run riot and of making the electric 
 farm of the future appear a very Utopia; there will 
 ever be plenty of hard work for the farmer, even on 
 the model electric farm, but he will have more 
 pleasure and satisfaction in his work, and, it is to 
 be hoped, more profit from it." 
 
" 
 
 
 50Tn-7,'l6 
 
YB 12383 
 
 
 UNIVERSITY OF CALIFORNIA LIBRARY