How Perspiring Plants Promote UCH of the healthful moisture in the air you breathe comes from perspiration of the plants, trees and grass around your home. For ex- ample, it has been found that the aver- age suburban lawn gives more than ten barrels of water to the air every sum- mer day. To distover such facts as these, Uncle Bam, master farmer, has recently been conduct- ing interesting experiments with ingénious de- vices, measuring and recording exactly the amount of water that "transpires" or evaporates from the leaves of plants in 24 hours. The results have revealed the astonishing rate at which growing things, absorbing water from the soll, pass it off into the air, thus serving as Nature's automatic humidifiers for the at. mosphere. One pot of alfalfa lost more than eight quarts of water in a single day, when the stmosphere was dry and the wind strong. The average amount of evaporation for a large plant like a sunflower is between a pint and a quart daily. Findings such as these show why potted Your Health plants in your rooms help to restore mols- ture to the heater: dried air which makes 80 many American homes unnealthful. How these experi. ments were conducted by the United States Bureau of Standards is described by Pop- ular Science Month. ly. Special weighing apparatus was devised for these measurements under natural conditions, in the open air. The plant is placed on the platform of a delicate How the Height of a Fog Is Measured by a Human Hair HE contracting effect of dry air upon hu- man hair was the means of suggesting the {invention of an ingenious device for measur- Ing the height of fogs in London. When fog descends upon England's great me- tropolis weather observers send up toy balloons attached to long cords at the end of which is fastened an instrument containing strands of ' hair. The latter is so ad. justed that the contrac- tion in dry air releases a little brass ring, which Jlips to earth. The ob- servers, knowing hew much cord they have paid yut, can theredpon gauge the height of the fog. This device is used in ¢he airplane traffic be- tween England and France, So greatly have aviators beén hampered by fog, that character. istic feature of British weather, that it often has been im ible to start, or at least altogether risky to venture into the air, from the starting! point at Croydon, even though reports from sta. tions five or ten miles slong the route showed ¢lear skies, for no ade- quate information could . be had of the extent and particularly of the depth of the fog. The manner in which this mechanical aid to aviation is worked out is described by a writer in the Scientific American. The rings are held in place on the cord, when the instrument starts its flight by a trigger-like catch. Attached to the butt end of this cateh is the hair, which passes over a little pulley-wheel shat acts as a fulcrum, and then runs up fg some inches through an The hair is damp to begin with when the ad- justment is made on starting the Bint, and » Jong as it remains in the damp, foggy air it re. a Human Hair. mains damp and nothing happens. When it peathes the clear, dry air above the top of the The Fog - Measuring Apparatus That Uses log, however, it contracts, and by virtue of the purchase given it in its passage over the fulcrum, it drags the catch-off to one side and releases $he ring. The latter is mounted around the cord ess ct cnn on which the apparatus goes up, so that it falls, hot freely, but down this cord. When it puts in its appearance at the lower end of this, the ob- servers know that the top of the cord has emerged into ¢fear weather, and, knowing how much cord they have paid out, they know how high the pilot must direet his plane in the search for fair weather. It is contemplated installing this weather- finder at close intervals along the Paris-London route, in conjunction with radio stations. The pilots of the planes will then be advised at all times how high they must go at various parts of their journey to get clear weather, and, among other things, to avold such accidents as the Ye- cent fatal collision in the fog. In addition, the uncertainty surrounding the question of whether a safe start might be made in thick weather would be resolved, and trips that are now lost could be made alike in safety and in comfort. The Plant Is Measured for Evap- oration by the Weighing and Re- cording Apparatus Shown at the Left. As the Plant Loses Weight, the Beam of the Scale Falls, Com- pleting an Electric Circuit That Drops a Ball Counterweight from One Portion of the Apparatus to 4s Another so as to Restore the Balance and Register the Amount of Evaporation scale, and carefully balanced. Any loss in weight thereafter, of course, is due to loss of water. As the beam of the scale falls, it completes an elee- tric circuit that opens a gate and allows a tiny steel shot to drop from ome portion of the ap- paratus to another, restoring the balance. Each steel ball corresponds to a loss of 20 grams on the part of the plant. The shot are kept in a coiled pipe, and fall into a cone-shaped receiver suspended on knife edges. A spring motor gives a positive lift to the scale beam every time a steel ball is dropped. The recording device is similar to those used on automatic rain gages. It has a drum 18 inches in elrcumference that makes a revolution every six hours, and is continually offset by a screw so that four six-hour periods are recorded side by side on the same sheet. In this way, besides de- termining the total amount of water the plant breathes into the air, the apparatus charts the loss in connection with the time elapsed and the local weather conditions. The apparatus works perfectly, except when sudden upward gusts of wind lift the plant, caus- ing the recording of a transpiration rate that is abnormally high. Special provision is made to prevent mote than one ball being delivered to the cone at a time, however, and no record is Jade unless a ball is actually deposited on the m. WHY the FARMER Has to PLOUGH farmer, it is estimated, will prepare about 40,000,000 acres of land for winter wheat Alone. And the cost of ploughing: and working this ground will exceed $140,000,000. Did you ever ask why farmers plough for wheat or why they cultivate for any erop? If you have perhaps yolit answer was mueh like the ohe D URING the present summer the American 'that L. E. Call, chief agronomist of the Kansas State College of Agriculture, says that his father used to give him. "As a boy I never ploughed or worked ground for wheat without wondering why," writes Mr. Call in Farm and Fireside, uirrel hunting and fishing were always good in August. Of course I had a chanee to do both, but it always seemed that the neighbor boys could do mote because our wheat ground always needed work. I asked my father why many times, but the only answer he could give was that the wheat next year would be better. This I soon observed, for our wheat always turned otit better than our neighbors' ever did at threshing time. "There was no subject that interested me more during my college days than why we eulti- vate the soil, and my interest in this subject prompted me to start at the Kansas State Agri- cultural College what is now some of the most extensive and oldest tillage work with winter wheat in the country, from the standpoint of con- tinuity. While climate and soil conditions are not the same in all states, the principles under- lying tillage practice are the same everywhere, and I am sure that a number of things that we have learned will be of interest and value to you. "There seems to be five things accomplished by ploughing and cultivating the soil. They are: 1. The tilth of tha soil is improved. 2. The soil is put in the best possible condi- tion to receive the seed or plant. 8. Organic matter is incorporated with the soil, 4. Soil water is controlled and moisture is conserved for the crop. 8. Food is liberated for the use of plants. "It is impossible to overestimate the impor. tance of good ploughing on the physical condi- sr a p-- Is LOVE at FIRST SIGHT Due to a PERFUME? T has been the experience of practically every one that on first meeting some persons he takes an instant liking to them, and that this liking is almost invariably returned, without there being apparently the slightest reason for it. Sei- entists explain that this is not a matter of reason at all, but of instinct, and nearly always occurs with highly sensitive persons who have an under- mind that is much nearer the surface than is the case with their more stolid neighbors. This under-mind is perpetually sending out, as it were, flashes of something that can perhaps be com- pared to wireless telegraphy, trying to pick up Wh rs mothe po an and s en nd another person an er- i ee mbar pein, With gn uhdes- Without WH lat knowing why. al Tails however, the usual explana a dor a ual splanttion a different thing, and which as yet is not thor- oughly understood. tion of the soil. Land that has been repeatedly hammered down by beating, packing rains can only be put into the best possible seed-bed e¢ondi- tion by ploughing. There is a time when every soll contains the proper amount of moist- ure to plough in the best tilth. If ploughed in a wetter or drier condition, the results accomplished will be less satisfactory. "The most satisfactory way of disposing of organic matter is with the plough. If we did not have an implement that would turn orgahic mat. ter under, materia: such as stubble, cornstalks, and weeds would accumulate in such quantities at the surface that in many cases they would in- terfere with other tillage tools, It is alse impor- tant to incorporate organic matter with the soil, 80 that it will decay properly and, in decaying, release from itself, and from other soil material, plant food for growing crops. If it is ever advis- able to plough deep--that is, deeper than six inches-~it is probably for the purpose of incor. porating organic matter with a greater volume of the minerai soil, and in that way build a lerger storehouse in which reserve supplies of plant food can be stored. At Rothamsted, the great English experiment station, 60 years of experimental work has shown that the subsoil is very poor in . plant nutrients, and nothing whatever is gained by bringing it to the surface." How ELECTRICITY Is MEASURED HE language of the electrician is Greek to most people. While he talks glibly of volts and amperes and watts, they know only that they have to pay an electric light bill for so many units, and let it go at that! Though electricity is not a fluid, most of its terms can be compared with water flowing through a pipe. Turn a stream of water onto the paddles of a water-wheel, the work that the wheel will do depends upon two things--the amount of water delivered every second and the pressure of the stream. The first 1s measured in gallons and the second in pounds. In the case of electricity, however, the rate at which it flows is measured in amperes and its JStunte in volta The work which it will do is m amperes and volts together, _which gives answer in watts, or units of energy. The unit is 1000 watts, often called a kilowatt, which is the electrical equivalent of one horse- er, You will find the number of watts they re- quire engraved on most lamps, and from this you ean discover what they cost to use. A 25-watt lamp will use one unit of 1000 watts in A New Bread to Form the Perfect Food of the Future LOAF of bread and a bottle of milk--these are the two items that will make up the daily meals of the future. This is not go- ing to be the case because of poverty or a strict diet, but because science has just discovered a new vitamine that will make bread the perfect food and enable the housewife to discard others. This is the picture drawn by no less an authority than A. B. Hess, graduate chemist of Johns Hopkins University, a professor for 16 years and now educational director for one of the world's greatest milling engineering concerns. "For the day is not far distant--it is within the span of even the oldest of us--when a loaf of bread will contain all the food values neces- sary to the most exacting stomach," said Prof. Hess in a recent address to the American Asso- ciation of Cereal Chemists. "Within this age bread will become the perfect food--complete in itself. It is only a matter of a few short years--months perhaps--when the American housewife can discard every side dish-- can put away her pots and pans, even discarding ker cven, and still be able to please the exacting palate of her husband--and all with a loaf of bread." Pref. Hese's prediction followed the announce- ment of a discovery by Dr. E. V. McCollum, also of Johns Hopkins University, of a new vitamine-- a fourth on the list of these mysterious new food properties, "The discovery of this new vitamine," said Dr. McCollum, "brings to the world a new mes- sage of hope from bodily diseares." Dr. McCollum classified vitamines "A," "B" and "C" and called the new unknown food force "D." The new vitamine is concerned in the etiology of bone growth and is the food substance which prevents rickets in children. The four vitamines, as listed by Dr. MeCol- lum, are: A--Prevents night blindness and sore eyes among children. B--Lack of this vitamine lowers the vitality and makes the body subject to infection. C--Prevents scurvy. POISONS to CURE N the reptile houses of some of the country's zoos you can see a rather large and ugly- * looking lizard, with a blunt head and a stumpy tail. The inscription on the cage tells you that its name is "Heloderma," and its home Arizona. This unpretentious creature is, in fact, the fa- mous or infamous "Gila monster," which is one of the only two poisonous lizards known to man. Until recently the best thing to be done with this deadly and uncouth inhabitant of Arizona's blazing wastes seemed to be to destroy it as soon as possible, yet now the advance of science has invested the monster with a sudden value. It has been found that the poison of the Gila monster is a useful remedy for that form of paralysis known as "motér ataxia," a disease whith prevents the proper use of the limbs, and was formerly thought incurable. The poiton is of such amazing strength that D---Protects hone growth and prevents rickets. "Heretofore we have known of three vitamines, substances which it is imposiible to isolate by chemical means, but which we know are essential to growth," Dr. McCollum explained. "We know now for a certainty of another one, and I believe we are only on the first road to find. ing more of these mysterious substances." Vitamines were first discovered in food when notice was taken of the unusual results animal growers were obtaining by feeding certain rations. "Every farmer knew young livestock would grow faster on yellow corn than white," the doe tor-chemist said. "Chemists did not know why. Investightion has revealed that the yellow color in corn is a vitamines=it is 'Vitamine B.' "All four vitamines Sire found in milk and the leafy parts of plwnts. Their absence from the diet of growing children tesulte in under-nutri- tion, bad teeth and rickets." Dr. McCollum emphasizes the importance of foods containing vitamines in the diet of ex- pectant mothers and also in the diet of the grows ing child. "The properties of vitamines were made known after laborious tests," he said. "However, what it is, or what a vitamine looks like, is unknown. It does not respond to chemical tests. "Vitamines are found in these foods: "Fat, soluble A, in milk, Shige, yell of eggs "Water, soluble B, milk, husks, or grains leaves of plants and spinach. "Anti-scurvy C, milk, ¢itrus fruits and potadt skins, and in combination with foods having the other two. "Cabbage is the highest food in vitamines; in the raw State it has two counts for A, one for B and three for C. Cooking lowers the fitet two. "Carrots have one count each for the three classes. Tomatoes have all three vitamines, and the curative qualities are not lost in eooking. Lettuce has two counts for A, two for B, but hong for C. "The day is eoming--and coming soon--<when the modern miller will combine the four vitamines in one loaf of bread," Prof. Hess predicts. "Then the American diet can be revived." ee] Deadly DISEASES it has to be diluted down to the one-hundredth. thousandth part. In other words, the solution used is one drop of the poison to somethihg over a gallon of alcohol. The poisons of many venomous snakes are now being used in medicine. Both the cobra and the rattlesnake ase kept inh nuribers ih oh) " 80 that their poison may be extracted for the manufacture of & serum for the cure of snakebite. The work of the Pasteur Institute in this direction ia well known, and quantities of theif serum go to India. Near Rio, in Brazil, is a State Institute for the manufacture of sera for the cure of shake- bite. Here are shakes of a score of different kinds, including the huge and terrible "bush- master," and the deadly little "coral snake." Brazil is full of pelsonous snakes, and the government sera are to be obtained in almost any village throughout that country. Growing MUSHROOMS on TREES ATURE, by cross Yertilization, has produced N many freaks and monstrosities. Every now and then you hear of soiie new prank she has played. As a rule, men don't ¢limd trees to gather mushrooms, though many of the mush- room's hear relatives flourish on growing trees. These fungi, if not edible, are at least very SONG of the SIREN T is well known that many new inventions in the physics, especially in the field of music, are made by using turn-rails, so-called sirens. The following experiment shows the effect of such a turning disk: : Cut a cog-disk from a piece of cardboard and make about one inch or two inches from the cen- tre two openings. Take a long string through interesting. Their beauty of structure, rapidity of growth, and brilliancy of 'color readily arrest attention. However, it might be well to warn mushroom hunterssto give these growths on trees a wide berth. The time may be at hand when Nature will eliminate the noxious elements, and these fantastic fairy stools will then be available as food for man. i In anticipation of the "mushroom-tree," the Japanese have adopted a system of tree culture for these delicacies. The Japanese method of ; securing a crop is unique in many ways, and is characteristic of their mental acuteness. Mush room growing is one of Japan's many industries, and several million dollars' worth reach the world's markets annually. In their unique methods of mushroom culture the Tapas: fell trees of huge growth which have adorned the forests for many decades. These are left to lie for a year or two. Large holes are then bored into the tree trunks, and spawn ine serted therein. Under Such ¢onditions they produce practical. ' ly a continuous crop, and grow with a "mushe room growth rapidity." To anyone familiay with the somewhat crude methods of producing mush- rooms in tunnels and other dark recesses, ed in this country, this system will Ap suggest a better method of culture. The growth of mushrooms is influenced eon siderably by changes of the moon. There is an old folk-lore rhyme in Essex with a considerable "When the moon is at the full, Mushrooms you may freely pull; When the moon is on the wane, Wait before you pluck again." Observers: of these night growths know at full moon the crop invarisbly shows itself, bus when on the wane there is a perceptible decline.