Vol. XXII. No. 4.J 



POPULAR SCIENCE NEWS. 



55 



l^ome, iFamt, anD Garten. 



THE GROWTH AND DECAY OF ROCKS. 

 The belief that rocks and stones, especially 

 the loose bowlders found in the drift, have 

 grown and are growing in their present situa- 

 tion, is not uncommon among ignorant people. 

 At certain points on the coast of Maine the 

 fishermen are unanimous in their belief that 

 the rocks in the harbors are growing, as they 

 find less water over them than in former years. 

 This is probably- true in one sense, as there 

 can be but little doubt that the land in those 

 localities is slowly rising. 



The early settlers of New England, in plough- 

 ing up their land for the first time, and finding 

 it filled with rounded rocks of every size, 

 from the tin}- pebble to the massive bowlder, 

 and knowing nothing of the great ice age and 

 the geological discoveries of more modern 

 times, might well have thought that the stones 

 had grown in situ by some concretionar}' pro- 

 cess ; but we now know that thej' are rather 

 diminishing than increasing in size, and that 

 they have all been transported from the parent 

 ledge by the irresistible power of moving ice, 

 in many cases for hundreds of miles. 



Nevertheless, it is true that many rocks 

 actually do grow. The limestones have been 

 formed bj- living organisms, like the coral 

 polypes ; and it ma}- even be said of many lime- 

 stone deposits, that every particle has at some 

 time formed a part of a living animal. Sand 

 stones, slates, and probably some varieties of 

 granite, have all been deposited underneath 

 large bodies of water, and in this sense have 

 gradually grown to their present dimensions. 

 Onl3' the igneous or volcanic rocks cannot 

 strictly be said to have "grown," and those 

 of this class which are highly crystalline may 

 be indirectl}' so considered, as the formation of 

 a crystal, either from fusion or solution, pre- 

 sents in many wa^'s a wonderful resemblance 

 to the growth of a living organism. 



It is, however, the decay of the rocks that 

 is of the most importance, and with which we 

 have most to do. The "eternal hills" are 

 not only often "shaken," but are very far 

 from being eternal. They are constantly de- 

 creasing in size, and being washed down into 

 the valleys. Even the lofty Alps are consid- 

 ered to be but the " stubs " or remains of a 

 much loftier range existing in past geological 

 epochs. It is to this constant degradation 

 and decay that the farmer owes his fertile 

 fields, as the soil from which he raises his 

 crops was at one time in the condition of 

 hard and barren rock. 



The agencies which cause the decay of the 

 rocks are very numerous and varied. Cold, 

 heat, frost, rain, wind, vegetation, running 

 streams, and standing water all do their part ; 

 and chemical decomposition is an important 

 factor, especially with granites and other 

 rocks containing felspar. Extremes of heat 

 and cold cause the surface of the rock to 

 crack, and the cracks become filled with water, 

 which freezes and exi)ands, breaking it up 

 still further. Every stream of water, from the 



trickling raindrops to the rushing torrent, 

 does its part in wearing away and pulverizing 

 the rocks in its course ; and the finelj- divided 

 material is carried along bj- them, and depos- 

 ited along its banks, or in the sea at its 

 mouth. In dry countries the sands of the 

 deserts, blown about by the winds, wear away 

 the rocks, just as, on a smaller scale, the sand- 

 blast cuts the hard gla.ss, and engraves beau- 

 tiful designs on its surface. 



In that wonderful natural laboratory which 

 exists in every growing plant, there are re- 

 agents which can slowly but surely act upon 

 the hard, stony particles in the soil, and cause 

 their decomposition. The wheat-stalk, for 

 instance, possesses the power of assimilating 

 from the soil that most refractory element, 

 silica, which the chemist can only dissolve by 

 the aid of his most powerful reagents, and 

 building it into its structure to give it the 

 requisite strength. In a similar waj', lime, 

 magnesia, phosphoric acid, and potash are all 

 derived from the soil, causing the further dis- 

 integration of the more or less fine grains of 

 sand or rock previously existing there. 



The decomposition, or " weathering," of 

 granite and other felspathic minerals is a 

 matter of much interest. Granite is a com- 

 posite rock formed of the minerals quartz, 

 mica, and felspar. Quartz is one of the 

 hardest and most permanent of minerals ; but 

 mica, and more especially felspar, contains 

 alkalies which are easii}- removed. Chemi- 

 cally speaking, felspar is a silicate of alu- 

 mina arid potash or soda. The chemical com- 

 bination is so weak, that, under the action 

 of the elements, the potash or soda is ren- 

 dered soluble and washed away, while the 

 silicate of alumina remains as a fine white 

 powder, known as kaolin or porcelain clay. 

 The large deposits of this valuable substance 

 in various parts of the world are supposed 

 to have been formed in this way bj- the de- 

 composition or weathering of felspar or fel- 

 spathic rocks. * 



We thus see that even in the mineral king- 

 dom there is a constant change. The solid 

 rocks are ground down into gravel, sand, or 

 clay of various degrees of fineness. The 

 streams transport them to the lower levels, or 

 spread them out over the ocean's bed. We 

 know that in the past these deposits have been 

 hardened and consolidated into conglomer- 

 ates, sandstones, schists, shales, slates, and 

 metaraorphic rocks, and raised up by the 

 contracting earth into hills and mountains 

 once more. Whether this process is ever to 

 be repeated, we do not know ; but as long as 

 the present natural forces are in operation, 

 we know that the Tuountains, hills, rocks, and 

 stones are continually decaying, and the sur- 

 face of the earth tending to one general level. 



STABLE MANAGEMENT. 

 Pure air is as essential to the blood as sound 

 food is to the sustenance of the body. Consumed 

 air is vitiated air, the volume of oxygen is reduced, 

 carbonic acid is in excess. The stable is full of 

 organic impurities given off by the skin and the 



lungs. Ventilation is found in all well-regulated 

 stables, and draughts are unknown, or ought to be. 

 But these are matters for individual consideration, 

 and are best settled by the builder. 



Hoises drink once or twice a day, and the horse 

 may be trusted to gauge his thirst, except on 

 occasion of extreme exertion, such as a hunting 

 morning. That all liorses are the better for being 

 watered before being fed is an admitted fact with 

 all veterinary surgeons and intelligent grooms. 

 Colic and gripes are thus avoided. The ex- 

 planation given is this: When the stomach is full, 

 water, passing rapidly through the stomach, on the 

 way is very apt to carry with it, into the small 

 intestines, undigested corn, and this produces local 

 irritation. There is less danger in watering a horse 

 actively warm than when the system is somewhat 

 lowered. In the latter case there is not sufficient 

 vitality to raise any considerable qiiantity of cold 

 water up to the temperature of the body: hence so 

 many chills supervene, bowels are deranged, and 

 the coat of such horses looks unthrifty, or, as we 

 call it, "stares." Soft water is better for all 

 stock, and on no account let horses drink dirty 

 water: it is most objectionable. 



Horses have small stomachs. We divide the 

 corn into three daily portions, the hay into two. 

 We never give hay just prior to work: it distends 

 the stomach, and causes the horse inconvenience. 



Delicate feeders must be tempted to take their 

 rations, and such should never be fed too strongly 

 at one time. "A Scotch plate" is the rule here, 



— every thing cleaned up before placing other food 

 in the racks or mangers. A little linseed boiled to 

 a jelly and mixed wilh the corn is seductive. Hay 

 damped and salted will tempt others. Tick-beans, 

 a double handful, are a relish in weakly subjects, 

 pale malt for the convalescent or indisposed; 

 damp bran and oats are engaging for others. 

 Some grooms give carrots and tares in small 

 quantities. Carrots superinduce diabetes if given 

 in excessive quantities. The peculiar habits of 

 horses demand the attention of all horse-owners 

 and grooms. A sufficiency of flesh is all that is 

 required, and not "hog fat," or "beastly fat" 

 as some phrase it. 



The quantity usually given to hunters and thor- 

 oughbreds is fourteen to sixteen pounds of oats 

 daily; i e., two and a quarter to two and a half 

 bushels per week. Carriage horses in town, ditto. 



Beans should be hard, dry, sweet, plump, sound, 

 not less than a year old, and weigh sixty pounds 

 to the bushel; a double handful each principal 

 meal, morning and night (about two pounds daily), 

 in the fall and winter months. New beans are 

 colicky feed, and less nutritious than old. Peas and 

 beans should always be split, to insure uniform 

 quality. 



Horses fed largely on other foods demand less 

 hay, but hay is useful in distending the stomach, 

 and thus assisting digestion. From six to fourteen 

 pounds daily; the average use is ten pounds in 

 many stables To maintain hunting or racing 

 condition, old hay is essential. 



Clover, vetches, and trifolium are laxative and 

 cooling, and excellent for the invalid horse or the 

 youngster. They should be given sparingly, at 

 the early part of the season. Green forage should 

 never be given to horses in fast work, except on 

 Saturday nights. 



Good grooming is demanded under stable 

 management and in fast work. The brush, as a rule; 

 should follow the direction of the hair, except 

 when dirt and sweat are caked onto the coat; 

 then you require to go against the lie of the coat 



— the set of the coat. Good grooming shortens 

 the coat, gives a gloss, and develops physical force. 

 When a good gloss is present, we know the effetes 



