796 



THE TROPCIAL AGRICULTURIST. 



[May I, 1884. 



shape than those of the wheat. Indead, we believe that 

 grains of corn are denser and of greater specific gravity 

 th^iu grains of wheat, and if both were of the same size and 

 shape a busliel measure of corn would weigh more than the 

 same measure of wheat. Now, a large grain of wheat con- 

 tains a less percentage of bran and a corre.sponding greater 

 percentage of flour. The thickness of peel being the same 

 in each of two apples, the smaller specimen will contain 

 tihe larger percentage of peel when compared with the whole 

 apple. So it is with wheat or other grain. This is based 

 on a well known geometrical principle that the solidity (or 

 contents) of .iny round or nearly round body increases in 

 a more lapid proportion than its siu-face. Large grained 

 wheat, then, will yield a smaller percentage of bran, and 

 therefore 60 lb. of large grained wheat will yield more flour 

 than 60 lb. of small grained wheat. In regard to relative 

 production per acre it is bald a.ssertion to say that an acre 

 will yield the same bulk of the same number of measured 

 bii.shels of heavy wheat as of hghter wheat, and that, there- 

 fore, the heavier is the more prolific or productive. Nature 

 deals by weight not by volume. — Colonial Southern World. 



CONSTITUENTS OF SOILS. 



AVTiat is silica? It is a substance which occurs in nature 

 more frequently and abundantly than any of the other earths. 

 Ail hard stones which give out .sparks when struck by steel ; 

 the enormous masses of granite, together with the vast 

 accumulations of sand in deserts and in plains, are mainly 

 composed of silica ; and there are few stones that do not 

 pontain more or less of this substance. .There is scarcely 

 a single plant that does not contain it. Grasses, in particular, 

 contain large quantities of it; and it forms the grass-like 

 coating on the straw of wheat. 



AATiat is alumina ? Alumina is the earth which, next to 

 silica, is found most frequently, and in the greatest abundance, 

 in our soils. Clay, into the composition of which alumina 

 always enters, exists in a greater or less degree in evei-y 

 soil, and is also fo\md in extensive strata beneath the sur- 

 face of the earth. Moreover, alumina forms a constituent 

 part of most stones, and in some it is the principal 

 ingredient. A small quantity of it is found in the ashes of 

 most vegetables. This earth is of great importance to the 

 agriculturist, in order to enable him duly to appreciate the 

 i]ifluence of clay upon his fields, and the improvement or 

 deterioration of the soil which it occasions. Alumina appears 

 to have a greater afluiity for water than any of the other 

 elementary earths. It has a very powerful afiinity for the 

 other earths, and in cert.ain cases enters readily into com- 

 bination with them. It has a very great tendency to unite 

 with silica. It is in consequence of this afiinity that silica 

 is so often combined with alumina in forming the compound 

 called clay. Lime also has a strong afiinity for alumina, 

 which exjilains the great fusibUity of these earths when 

 pijxed. jUnmina exercises only an indirect influence on 

 vegetation, by its power of attracting and retaining water 

 and ammonia. It is itself very rarely found in the ashes 

 of plants. 



What is potash ? Potash is procured from the ashes of 

 plants, l)y burning and other processes. The plants which 

 yield the greatest proportion of potash are wormwood and 

 i urmitory. Refined potash is called pearlash, and is, in that 

 state, an impure carbonate of pota.sh, or potash with carbon. 

 AVood ashes are certainly a valuable manure, and are pecuharly 

 well adapted for gravelly soils and loams. This remark 

 ajJijlies to the ashes of almost every description of veget- 

 able land weeds, grasses, peat and sea weeds. 



■What is soda? Soda is obtained chiefly from two sources, 

 the burning of marine vegetables, such as common sea 

 weed, which furnishes the alkali called kelp; and the decom- 

 position of salt. A material purpose which these carbonates 

 (carbonate of potash and carbonate of soda) are .supposed to 

 serve is that of combining with and rendering soluble the 

 vegetable matter of the soil, so as to bring it into a state 

 in which it may be readily taken up by the roots. They 

 may in this case be said to prepare the food of plants. 

 This mode of action can bo exercised in its fullest extent 

 only where vegetable matter abounds m the soil. They are, 

 therefore, most useful where vegetable matter is plentiful, 

 and ought to be employed more sp.aringly and with some 

 degree of caution where such organic matter is deficient. 

 .Another mode in which these substances act, more obscurely 



perhaps, though not less certainly, is by disposing the organic 

 matter.s contained in the sap of the plant to form such 

 new combin.ations as may be required for the production 

 of the several parts of the Uviug vegetable. 



What is Ume? Lime is one of the most abundant sub- 

 stances in nature; it forms whole mountain chains, and 

 together with other earths and metalUc compounds con- 

 stitutes a great number of minerals. It forms a constituent 

 part of all vegetables; and in animals it forms the principal 

 ingredient of shells and bones. In its chemical constitution, 

 Hme is composed of a peculiar metal called calcium ancl 

 oxygen. 



What is magnesia? Magnesia is an earth le.ss abundant 

 than lime. It is never met with piu-e, but always mixed 

 with other earths, and combined with acids. Several minerals 

 contain proportions of it; springs, rivers, the sea and salt 

 water also contain it. The ashes of most vegetables con- 

 tain it ; it sometimes forms a very considerable constituent 

 part of the layer of vegetable mould, and of that marl 

 which is best adapted for the purpose of manure. The bam 

 of flour contains a large quantity of ammoniacal pho.sphate 

 of magnesia. This salt forms large crystalline concretions, 

 often amounting to several pomids in weight, in the c:BCum 

 of hor.scs belonging to millers ; and when ammonia is mixed 

 with beer, the same salt separates as a white precipitate. 

 Liebig makes an important division of plants, according 

 to then- propositions of these organic substances. Thus: 

 potash plants he defines to be those the ashes of which 

 contain more th.au half their weight of soluble alkaline 

 salts. Lime jjlants and sihca plants are those in which lime 

 and silica respectively predominate. The ingredients thus 

 indicated are those which form the distinguishing character- 

 istics of the plants which require an abundant supply of 

 them for their growth. The potash plants include the beet, 

 mangel-wurzel, turnip, maize, &c. The lime jjlants com- 

 prehend clover, beans, jjeas, tobacco, &c. The sihca plants 

 include wheat, oats, rye and barley. The potato belongs 

 to the lime plants, as far as regards the ingi-edients, of 

 its leaves, but its tubers (which contain only traces of lime) 

 belong to the classof potash plants. — Ynora Reason Why. 



CACTACEOUS PLANTS. 

 Grotesqueness of form or habit is rarely found in combin- 

 ation with floral beauty in the vegetable world, yet no 

 family affords more remarkable examples of this union of 

 widely divergent qualities than the great and peculiar Cactus 

 order. In many large groups of plants we find numbers 

 possessing handsome foliage, but having only insignificant 

 flowers, and in many others also, when the flowers are more 

 than usually attractive, the fohage appears chiefly to serve 

 the purpose of a foil to their rich or bright colors, having 

 in itself nothing of a specially striking nature. There seems 

 to be something of Nature's economy in thus developing 

 one particular quality at the e.x]>ense of the others — a con- 

 centration of strength, which probably has a deeper mean- 

 ing than we can perceive, for it is observable in the animal 

 kingdom as wi;ll as amongst plants. The Cactus family is, 

 however, an extraordinary exception, for whether flowering 

 or not, the majority of the plants constituting it are dis- 

 tinguished by most striking characters. They do not possess 

 beautifully colored or elegantly formed foliage to recommend 

 them ; on the contrary, true leaves .are absent from nearly 

 all, but in contrast to some of the most gorgeous flowers 

 produced by plants, we see unwieldy masses of vegetable 

 matter, spherical, cylindrical, or angular, armed with stout 

 and formidable spines, and resembling what we might al- 

 most imagine to be the relics of a vegetation belonging to 

 a period long prior to the development of the plant life 

 familiar to us in the present age. Such would be the first 

 impress on ; luit when the brilliantly colored rose, crims<in 

 purple or yellow blossoms were seen, the observer wou'd be 

 led to the conclusion that while the plant was advancing 

 to so high a degree of floral beauty, one portion of its 

 constitution nuist have been strangely stunted and altered 

 by soTue external, long continued forces. There is an 

 inconsistence of characters that must impress the least 

 observant, .and imparts an interest to the plants which 

 increases with the knowledge .we gain respecting them, 

 for they arc surrounded as it were by a degree of mystery 

 that always adds a charm to nature. Cactaceous plants 

 have, therefore, much to recommend them to lovers o 



