I860.] 



THE SOUTHERN PLANTER. 



471 



acid to supply 95,000 acres of wheat, 184,- 

 000 acres of potatoes, or 280,000 acres of 

 oats, and to hold in solution a sufficient 

 quantity of silica to supply 50,000 acres of 

 wheat.'^ 



A distinguished agricultural writer in 

 1845 makes the following remarks upon 

 the subject of the sewerage of London : 



*^By carefully conducted experiments and 

 very accurate gaugings, it has been found 

 that the chief London sewers convey daily 

 into the Thames about 115,000 tons of mix- j 

 €d drainage, .consisting, on an average com- 

 putation, of one part of solid and twenty- 

 five absolutely fluid matters; but if we only 

 iillow one part in thirty of this immense 

 mass to be composed of solid substances, 

 then we have the large quantity of more 

 than 3,800 [toos] of solid manure daily 

 poured into the river from London alone, 

 consisting principally of excrements, soot, 

 and the debris of the London streets, which 

 is chiefly carbonate of lime; thus, allowing 

 twenty tons of the manure as a dressing for 

 an acre of ground, there is evidently a 

 quantity of solid manure annually poured 

 into the river equal to fertilizing more than 

 50,000 acres of the poorest cultivated land ! 

 The quantity of food thus lost to the coun- 

 try by this heedless waste of manure is 

 enormous; for only allowing one crop of 

 wheat to be raised on these 50,000 acres 

 that would be equal to the maintenance 

 (calculating upon an average produce of 

 three quarters of wheat per acre) of 150,- 

 000 persons. London, too, is only one 

 huge instance of this thoughtless waste of 

 the agricultural riches of the soil of Eng- 

 land. From every other English city, every 

 town, every hamlet, is hourly passing into 

 the sea a proportionate waste of liquid ma- 

 nure ; and I have only spoken of the solid 

 or mechanically suspended matters of the 

 average ; the absolutely fluid portion i§ still 

 rich in urine, ammoniacal salts, soda," &c. 



The earth is surrounded by water in a 

 tstate of vapor, and the quantity varies ac- 

 cording to the temperature of the atmos- 

 phere and other circumstances. Verner 

 found as a mean of fifty experiments, in 

 1,000 parts of air, 8.47 parts of vapor. In 

 the forenoon, and before two o'clock, the 

 mean was 7.97 ; and between two p. m. and 

 evening, 8.85. There is more humidity in 

 the atmosphere during the day than at 

 night; and more during the summer than 

 winter; more in low, flat countries than in 



mountainous regions ; and less in the inte^ 

 rior of continents far removed from rivers, 

 lakes, or the ocean. A slight change in 

 the temperature of an atmosphere, saturated 

 with humidity, produces fogs, clouds, and 

 rains; and by congelation, snow, &c. A 

 continuous evaporation takes place from the 

 ocean, lakes, rivers, and the soil, and a re- 

 turn to the earth in form of dew and rain. 

 The amount of evaporation that takes place 

 in a country is greatly influenced by the 

 ( operations of the farmer. In a report made 

 by Andrew Brown and Dr. M. W. Dickeson 

 to the American Association, in 1849, those 

 gentlemen remark : " that the annual quan- 

 tity of rain that falls in the valley of the 

 Mississippi may be estimated at 169,128,- 

 960,000,000 cubic feet, which is about 11|, 

 or 11.3636, times the quantity which is dis- 

 charged by the river. There can be but 

 two ways by which this immense quantity 

 of water can make its escape from the val- 

 ley; one is by the course of the river, and 

 the other by evaporation ; 8-91 parts are 

 carried off by the river, and 83-91 parts by 

 evaporation. Thus, we arrive at a fact of 

 the most momentous importance to the 

 planting interests of Louisiana and Missis- 

 sippi ; for it will be at once perceived that 

 the more exhalations are promoted, the less 

 liable will the low or bottom lands of these 

 two States be to the periodical inundations 

 by the river. 



" If it be asked by what process it is ex- 

 pected that evaporation can be promoted 

 over such an extensive area as the Missis- 

 sippi valley, so as visibly and permanently 

 to affect the planting interests of the above- 

 named States; the answer will be found in 

 the fact that the process has been, and is 

 now, in the most rapid and successful pro- 

 gress, and of that kind which is the best 

 calculated to produce so desirable a result, 

 viz: the clearing of such large portions of 

 the valley of its forests for the promotion 

 of agriculture, and the consequent exposure 

 of the lands to the action of the sun and 

 winds, the very best promoters of the evap- 

 orating process, particularly on a large scale. 



" So rapid is the progress of this increased 

 exposure, and its consequent evaporating 

 tendency, and so visible have been its effects 

 on the Mississippi river, that we may hazard 

 the assertion with safety, that there 's not 

 now, by twenty-five per cent., as much water 

 passing down the Mississippi as there was 

 twenty-five years ago; for at and prior to 



