No. 4. 



Magnesian Lime. 



115 



tages of an improved system of agriculture, 

 the brag crops do not appear to have been 

 increased, or those of former years even 

 equalled, since the introduction of magne- 

 sian lime ; but the general effect has been 

 similar to that produced in South-eastern 

 Pennsylvania; the facility with which the 

 lime can be procured, gives it a general in- 

 troduction into every part of the State. Mag- 

 nesian lime is enriching the soil, because the 

 good effects of the lime more than counter- 

 act the bad effects of the magnesia. 



According to the analysis of Posselt and 

 Reiman, " 10,000 parts of the leaves of the 

 tobacco plant contain 16 parts of phosphate 

 of lime, 8.8 parts of silica, and no magnesia; 

 while an equal quantity of wheat straw con- 

 tains 47.3 parts, and the same quantity of the 

 grain of wheat, 99.45 parts of phosphate." 



These experiments upon tobacco and 

 wheat, throw some light on the subject in 

 dispute. 



It is well known that tobacco is one of the 

 greatest impoverishers of the soil of any 

 plant we raise ; whole districts of the most 

 fertile land in the country have been ren- 

 dered totally barren by its cultivation. 



The analysis above stated, proves that no 

 magnesia had been extracted from the soil 

 upon which the tobacco was raised, and I 

 presume no one will suppose that the soil 

 contained no magnesia; the experiment then 

 shows that the presence of magnesia, with- 

 out lime, is not sufficient to keep up the fer- 

 tility of the soil: the tobacco having ex- 

 tracted all the lime and no magnesia, is a 

 case exactly to the point at issue; — we have 

 a soil containing magnesia and no lime, and 

 a more barren soil cannot be found. 



By this experiment we see the tendency 

 the wheat plant has to absorb phosphates; 

 and where magnesia abounds, we may rea- 

 sonably conclude that the quantity taken up 

 in the growth of the plant, injures the quality 

 and lessens the quantity of the seed. 



That the quality of grain generally, may 

 be injured by too much magnesia entering 

 into its composition, is shown by numerous 

 facts and experiments. Liebig says, "we 

 may form an idea of the quantity of phos- 

 phates of magnesia contained in grain, when 

 we consider that the concretions in the coe- 

 cum of horses, consist of phosphates of mag- 

 nesia and ammonia, which must have been 

 obtained from the hay and oats consumed as 

 food. Twenty-nine of those stones were 

 taken after death, from the rectum of a 

 horse belonging to a miller at Eberstadt, 

 weighing three pounds. F. Simon has lately 

 described a similar concretion found in the 

 horse of a carrier, which weighed one and a 

 half pounds. According to the experiments 



of Rouvelle and Brande, " The urine of swine 

 contains a large quantity of the phosphate of 

 magnesia and ammonia; and hence it is that 

 concretions of this salt are so frequently 

 found in the urinary bladders of these ani- 

 mals." 



These experiments prove the dangerous 

 nature of magnesia when combined with 

 food for animals; and reasoning from what 

 we know of the effects of magnesian lime 

 and pure lime, will lead us to conclude that 

 it is equally injurious to plants. 



I do not say that magnesia in small quan- 

 tities, is useful or injurious to the growth of 

 wheat; upon this point there appears to be 

 no evidence for or against, but there is cer- 

 tainly much evidence to show that magnesia 

 when applied as a manure, maybe increased 

 to a very injurious extent; which is the case, 

 as we suppose, in South-eastern Pennsylva- 

 nia, where magnesian lime, or lime in spite 

 of magnesia, is producing such wonders in 

 agriculture. 



Sand, clay and lime, are the principal con- 

 stituents of different soils that are in any 

 degree productive of vegetation; magnesia 

 enters into the composition of many plants, 

 but its presence in a plant is no evidence of 

 its being suitable food — it is only evidence 

 that the plant has taken it in as food. It 

 may have received it in the same way that 

 sheep eat the leaves of laurel, and birds eat 

 poisonous berries, because they can get no- 

 thing better. 



Plants, as well as animals, are sometimes 

 forced to take in food that stultifies their 

 growth, lessens their powers of production, 

 and ultimately terminates their existence. 

 It is now well ascertained that there is a 

 peculiar poison sometimes generated in salt- 

 ed provisions, that slowly insinuates itself 

 into the system of those who feed upon 

 them, until it produces disease and death. 

 The disease produced by this poison, was 

 known long before the cause and the means 

 of avoiding its evils were discovered. 



In this way, the disease among horses and 

 swine, produced by feeding upon seeds and 

 plants impregnated with too much magne- 

 sia, may have been destroying hundreds of 

 those useful animals, in South-eastern Penn- 

 sylvania; and the overcharged quantity of 

 magnesia introduced into the soil by lime, 

 may have prevented the growth of thousands 

 of bushels of wheat, and the inhabitants be 

 as ignorant of the cause, as those who for 

 hundreds of years, have been subject to dis- 

 ease and death from eating a peculiar kind of 

 salted provisions. 



These experiments show that magnesia 

 enters into the composition of plants to an 

 injurious extent, in the economy of animal 



