693 



THE IRRIGATION AGE. 



4. Porosity. This means that the atoms or molecules 

 composing any body do not touch each other; but are sep- 

 arated from each other by vacant spaces. That this is so is 

 plain, from the fact that the size of any body will change under 

 certain conditions without changing the amount of matter in 

 the body. Thus in Fig. 2 in the square A B C D is shown 

 an aggregation of 16 atoms, having spaces between them 

 representing the pores, which is the property of porosity. 



5. Expansibility and Contraction. These two properties 

 mean that the volume of bodies under the influence 



forces may 

 d i m i nish. 

 p r o d u c 

 changes are 

 t i o n s in 

 ature and 

 G- Thus if a 

 is heated it 

 length a s 

 width, and 

 a square plate 

 of steel which under the influence of heat is expanded 

 to the size E, F, G, H, it is plain that as the weight 

 remains the same, the number of atoms has not been increased 

 and it is the pores which have become larger or, with other 

 words, the particles have moved away from each other. This 

 same effect may be produced by applying external force 

 tending to pull the molecules or atoms away from each other. 

 The reverse phenomenon or contraction takes place when 

 a drop of temperature occurs, or when the body is subjected 

 to pressure, tending to force the particles together. This is 

 seen in Fig. 2 when considering the atoms in E F G H, 

 moving closer together when the volume decreases, as indi- 

 cated in A B C D. 



6. Indestructibility. This general property of all bodies 

 means that no matter can be either destroyed or created, and 

 that the total sum of atoms in nature remains unchanged. 

 That this is so is perhaps not always easily seen, but a little 

 study and thought will always confirm this statement. For in- 

 stance, if a ton of coal is burned the residual ashes may 

 weigh only a few hundred pounds; what has become of the 

 remaining matter? Chemistry proves that the remainder has 

 been converted into volatile substances which have passed off 

 in the form of smoke and vapor, and that there has nothing 

 been lost ; the hydrogen contained in the coal has been com- 

 bined with the oxygen of the air to form water, and the car- 

 bon has united with other portions of the oxygen of the air 

 to form carbon dioxide, both combustion products being in the 

 form of an invisible vapor have passed into the outer air. 



But there is no particle of matter ever lost in the econ- 

 omy of nature, and the different elements merely change 

 position when going through chemical or other changes. 



AMERICAN ENGINEERING CORPORATION 

 ENGINEERS. 



The American Engineering Corporation has been or- 

 ganized to conduct a general engineering business along 

 broader lines than are open to the individual engineer. 

 The Corporation commands the services of experienced 

 engineers, and is prepared to undertake work in all 

 branches of engineering. Engagements will be accepted 

 without limit as to locality, and the corporation is ready, 

 not only to act in the capacity of engineer, but also to 

 take charge of development and construction work from 

 inception to completion. 



Reports on investments will be made for financial in- 

 stitutions. 



The offices of the Corporation are located in the Me- 

 chanics Institute Building, 57 Post street, San Francisco, 

 California. 



Notes on Practical 

 Irrigation 



D. H. Anderson 



How Plant Food Is Transformed Into Plants. 



The growth of plants from the seed to the harvest, or 

 fall of the leaf, may be divided into four periods, during 

 each of which they live on different foods and expend their 

 energies in the production of different substances. 



This is important to be well understood, for plants 

 can not be dieted like animals, they need certain provi- 

 sions at certain periods of their growth, and if not sup- 

 plied with them the result is failure, or a sparse crop. A 

 farmer feeds his chickens egg-producing food, his cows 

 milk-generating fodder and mash, and his cattle fat-making 

 provender. He might as well deprive his animals of their 

 necessary stimulating food and expect them to go on lay- 

 ing eggs, furnishing milk and growing fat, as to expect 

 his crops to succeed without providing them with the 

 requisite material to arrive at perfection. But, to pro- 

 ceed. 



These four periods in the life of plants are: 



First The period of germination, that is, from the 

 sprouting of the seed to the formation of the first perfect 

 leaf and root. 



Second From the unfolding of the first true leaves 

 to the flower. 



Third From the flower to the ripening of the fruit or 

 seed. 



Fourth From the ripening of the fruit, or seed, to 

 the fall of the leaf and the return of the following 

 spring. 



Of course, in annual plants, when the seed or fruit 

 is ripe or harvested, there are no more duties or func- 

 tions to perform, hence the plants die, having accom- 

 plished the object of their existence. But in the case of 

 perennial plants, there are important things to be done 

 in order to prepare them for the new growth of the ensu- 

 ing spring. 



Period of Germination. 



1. To sprout at all, a seed must be placed in a suffi- 

 ciently moist situation. No circulation can take place, 

 no motion among the particles of the matter composing 

 the seed, until it has been amply supplied with water. 

 Indeed, food can not be conveyed through its growing or- 

 gans unless a constant supply of fluid be furnished the 

 infant plant and its first tender rootlets. This does not 

 mean drenching the immature plant with water, but sup- 

 plying it with moisture. A child needs feeding just as 

 much as an adult, but not to the same extent, and over- 

 feeding kills the young plant as quickly as the young 

 animal. The reason is plain, if the reader remembers what 

 was said in the last article, in which it was specified that 

 water is a chemical compound of oxygen and hydrogen. 

 In this state it is too strong a food for the young plant, 

 and "drowns" it out, as the saying is. But in a state of 

 moisture, the chemical nature of the water is altered some- 

 what and becomes available to the juices in the seed, 

 whereby the germ is enabled to grow and fulfill its mis- 

 sion without meeting with a premature death. It is water 

 that is the parent of moisture and without water, of course, 

 there can be no moisture. Nevertheless, throughout this 

 entire series of articles it is moisture that will be insisted 

 upon; when plants have that, the whole object of irrigation 

 will be accomplished, unless it be the intention to grow 

 aquatic plants. 



Now, this moisture must be constant during the entire 

 life of the plant, not liberal one day with the next day 

 dry, and so on, alternately, as some say may happen in 

 the case of pork for the purpose of making alternate layers 

 of fat and lean in the bacon, but not in the case of vege- 

 tation. 



2. A certain degree of warmth is necessary to germin- 

 ation. This warmth varies with the seed, some seeds, 

 those containing much starch, for instance, requiring more, 



