AGRICULTURAL CHEMISTRY AND GEOLOGY. 183 



I will here enumerate — namely, lime, as air-slaked lime ; magnesia, as air-slaked magnesia ; 

 phosphate of lime, or bone-earth ; sulphate of lime, or plaster of Paris ; carbonate of potash 

 and soda, with silicate of potash and soda, and also chloride of sodium or common salt, — all 

 indispensable to the growth and production of plants which are used for food. Pure rain 

 water, as it falls, would dissolve but a very small proportion of some of these substances ; 

 but when it becomes soaked into the earth, it there becomes strongly imbued with carbonic 

 acid from the decomposition of vegetable matter in the soil, and thus acquires the property 

 of readily dissolving minerals oh which it before could have very little influence. 



I was first led to the consideration of the above subjects by finding, on the re-examination 

 of a soil which I analyzed three or four years ago, a larger quantity of a particular mineral 

 substance than I at first found, as none had been applied in the mean time. The thing was 

 difficult of explication until I remembered the late long and protracted drought. I then also 

 remembered that in Zacatecas and in several provinces in South America, soda was ob- 

 tained from the bottom of ponds, which were dried in the dry, and again filled up in the 

 rainy, season. As the above explanation depended on the principles of natural philosophy, 

 I at once instituted several experiments to prove its truth. 



Into a glass cylinder was placed a small quantity of chloride of barium in solution ; this 

 was then filled with a dry soil, and for a long time exposed to the direct rays of the sun on 

 the surface. The soil on the surface of the cylinder was now treated with sulphuric acid, 

 and gave a copious precipitate of sulphate of baryta. 



The experiment was varied by substituting chloride of lime, sulphate of soda, and car- 

 bonate of potash, for the chloride of barium ; and on the proper reagents being applied, in 

 every instance the presence of those substances were detected in large quantities on the sur- 

 face of the soil in the cylinder. Here, then, was proof positive and direct, by plain experi- 

 ments in chemistry and natural philosophy, of the agency, the ultimate beneficial agency of 

 droughts. 



"We see, therefore, in this, that even those things which we look upon as evils by Provi- 

 dence, are blessings in disguise, and that we should not murmur even when dry seasons 

 afflict us, for they, too, are for our good. The early and the later rain may produce at once 

 abundant crops ; but dry weather is also a beneficial dispensation of Providence, in bringing 

 to the surface food for future crops, which otherwise would be forever useless. Seasonable 

 weather is good for the present ; but droughts renew the storehouses of plants in the soil, 

 and furnish an abundant supply of nutriment for future crops. — James Higgins, Mary- 

 land State Chemist. 



New Method of Using and Dissolving Bones. 



At a recent meeting of the Hillsborough Agricultural Society, at Manchester, New Hamp- 

 shire, General Riddle being called upon by the president to relate his experience in the use 

 of guano and other special manures, made some statements in regard to the way of dis- 

 solving and using bones, of which the following is a condensed summary : — 



General Riddle took sixty gallons of ley from oyster-shell lime to two hundred pounds of 

 bones, and boiled them together a few hours, and the bones were all dissolved or reduced to 

 a powder. A bushel of lime, he says, will make six gallons of ley ; and further, that bones 

 dissolved or reduced in this ley make a dry powder, which may be applied like ashes. He 

 put a gill of this powder to a hill, on twenty rows of corn, and omitted it on five rows 

 through the field. There was an astonishing difference in the appearance of these different 

 portions of the field. The corn where the bone-dust was applied was much the largest, and 

 of a far deeper green in color. — NasKs Valley Farmer. 



Liebig's Fifty Propositions. 



The following fifty propositions are copied from the recent work of Liebig on Agricultural 

 Chemistry, or his reply to the statements and experiments of Messrs. Lawes and Gilbert. 

 These fifty propositions are claimed by him to be distinct truths, established by the 

 researches of chemistry as applied to agriculture. 



