WHAT PLANTS ARE MADE OF.

New Zealand Mail, Issue 1118, 4 August 1893, Page 5

WHAT PLANTS ARE MADE OF.

THE FOUR CHIEF ELEMENTS. A manufacturer who commences business with a view to the production of a certain article must know of what that article consists, what raw materials are needed for its manufacture, and how they are to be wrought- up into the article desired. Thus the carriagemaker knows that a finished vehicle will require wood, iron, steel, leather, paint, varnish, &C; He must have a stock of these materials on hand, he must know how to prepare them, how to combine them, and, by the joint assistance of knowledge and practical skill, he is enabled to produce a carriage. So in other occupations.

The farmer is in a sense a manufacturer ; his workshop is out of doors ; the materials he has to work with are found in the air and soil; his tools are the implements of husbandry; and his products are the various plants that form the food of man and beast. If he would produce wheat lie ought to know of what it consists, out of what raw material it can be made, and by what means it is to be furnished So, if he would produce grass or potatoes, or any other crop, he should know what they are made of, whence the raw material is to be supplied, and how it is to be transmuted into the desired article. The carriage manufacturer finds his material in the form of certain compound substances, while the farmer must look for his material in the simple elements of nature. What these are, and how he is to avail himself of them, it is the office of agricultural chemistry to explain. A plant is a compound thing. It may be separated into its original elements. The simplest way of doing this is by burning it. If a plant be subjected to the action of fire, the greater part of it ‘ burns away/ as we are accustomed to say—it goes off in the various gases of vapour, until at length only a little ash is left. That which ‘ burns away ’ is called the organic part of the plant, and that which remains in the form of ash is called inorganic. Sometimes these two classes of material are called combustible and incombustible.

Now, it is a similar fact that plants of all kinds consist, as to their organic parts, chiefly of four different substances known as carbon, oxygen, hydrogen, and nitrogen. The inorganic matter found in them, and which is but small in proportion to the quality of oiganic matter they contain, embraces a variety of substances, the chief of which are phosphoric acid, sulphuric acid, potash, soda, lime, magnesia, iron, and chloride of sodium. As an illustration of the extent to which the organic constituents preponderate over the inorganic, it mhy be stated that if any hard-wood tree be cut down and burnt, for every 1001 b of wood there will be left only about 3|lb of ash. Small, however, as the inorganic element is, it is far from being unimportant It is absolutely necessary to the life and growth of tho plant —so much so, that if any portion of it be absent the plant cannot be produced in perfection. Every farmer ought to be familiar with the properties of the four chief constituents of all that lives and grows on the face of the globe. They are the raw materials, as it were, which the tiller of the soil is to manufacture into the various forms of vegetable growth.

Once familiar with this elementary substances, it is comparatively easy to understand the functions of plants, and the circumstances favourable to their production. A few words in reference to the nature and properties of these elements will be at least useful to young students of agriculture. Carbon is familarly known as common charcoal, and is widely distributed throughout nature. One has only to char a piece of wood to find out how large a proportion of vegetables consist of this substance. It cannot be dissolved in water, but it possesses the property of absorbing a certain amount of water, and being at once porous and incapable of putrefaction, it absorbs the offensive smells emitted by decaying matter, and even retains the lighter part of manures. It is when combined with oxygen in the form of carbonic acid gas that this substance becomes available for plant food. Strange to say this gas is a narcotic poison, which, if inhaled by human beings in sufficiently large quantities, produces stupor, insensibility, and death. It is this gas which destroys life when a person stays too long in a close room where there is a pan of burning coals. By a remarkable provision of nature, what is fatal to the animal system is a great source of life, health, and growth in the vegetable world.

Oxygen is the vital part of the air we breathe. It is essential to animal life, and without it there could be no combustion. Jn its pure state it cannot be easily distinguished from common air. It is void of colour, taste, and smell. It forms 28 per cent of the air we breathe, and eight parts out of nine in the composition of water. It is widely diffused, and has a tendency to penetrate everything with which it comes in contact. The rust that forms on iron exposed to the air or moisture is caused by the action of oxygen, which, combined with iron, oxidises it, and makes what is familiarly known as rust, but is called by chemists oxide of iron. combines with metallic ores, enters into the composition of rocks and earth and the bodies of animals, while it constitutes move than one third of most vegetable substances. Hydrogen is, like oxygen, a gas without colour, taste, or smell, and when pure is scarcely distinguishable from common air, though it is fourteen times lighter. On account of its extreme lightness it is used to inflate balloons. It does not usually exist in a gaseous state, though it can be easily obtained in that form. It combines with all animal and vegetable sub. substances, abounds in water, and is found in coal. Combined with oxygen it forms water; and with carbon it forms the common coal gas with which our houses and streets are lighted. Plants derive what hydrogen they contain from the compounds of this substance, chiefly from water. Nitrogen is another gas without colour, taste, or smell. It exists largely in the atmosphere, forming about 77 per cent of its bulk, and being apparently designed to dilute the oxygen of the air, and prevent it acting too powerfully on living beings and dead matter. Combined with hydrogen it forms ammonia, which is a most essential article of plant food. The smell given off by a dung heap, and often found lingering about stables, is caused by ammonia, which, being very light and volatile, escapes almost as quickly as formed, unless means are adopted to retain it as prisoner for future use- Jt is a most valuable commodity, but one which is recklessly wasted by nearly everybody who keeps a living creature on his premises. Such is a brief account of the simple elements of which the organic part of plants is formed ‘ Thistledown/ in Australasian.

Mr William Nelson has been interviewed in London, where he is now on a visit. He said :— ‘ lam home now mainly in the hope of making some better arrangement in the direction of freights. Not that I expect the shipping companies to reduce freights, which are about as low as they well can be; but if some understanding could be come to in respect of more regular shipments, in that way a saving could easily be made.’ ‘ Lord Onslow’s bill providing for the branding of imported meat is a wholly useless and mischievous one,’ continued Mr Nelson. ‘lt would be extremely costly and inconvenient to carry out, and it would be useless as a means of identification, because a carcase could not he branded all over. If one leg is branded, who is to identify the other leg and the shoulders when sold separately V