THE FARMER'S MAGAZINE. 



231 



filtered through a soil similar to a nitre-hed, is tainted 

 with substances evidently injurious. So true is it that a 

 condensed population carries in itself the germs of insa- 

 lubrity. 



At Paris, by reason of the geological medium which it 

 passes through, the water collected in the wells is not 

 drinkable ; nor is it drunk, or made use of in the pre- 

 paration of food. According to that, we might suppose 

 the population completely sheltered from the inconve- 

 niences which it would produce. This would be an 

 error ; for it is easy to prove that every inhabitant takes 

 every day the whole of the substances dissolved in a cer- 

 tain volume of that water. 



First, we are convinced that within the city walls 

 the lixivium {coupages) of the heavy wines and alcoholic 

 drinks are mixed with the water of the wells ; and it is 

 asserted that the bakers employ no other in making the 

 bread. 



One thousand kilogrammes of flour, in making into 

 bread, require for the different leavens and dough 617 

 litres of water. 



For produce they obtain 1,375 kilogrammes of bread, 

 containing necessarily all the soluble substances of the 

 617 litres of water. 



In 1 kilo, of bread there is therefore all that is found 

 in 45 centilitres of well water. Let us next see which 

 nitrates this water introduces. 



The well water of the Hotel Scipion, the bakery of 

 the hospitals, contains per litre the equivalent of 0.31 

 gr. of nitrate of potash : this is one of the waters least 

 charged with salts. 



One kilo, of bread prepared with this water should 

 contain O.l^- gr ; and 1 kilo, made with the water of 

 the well of Rue Saint Landry contains the equivalent 

 of about 1 gramme of nitrate of potash. 



In these weak proportions it is doubtful whether 

 the nitrates are unhealthy ; but what renders their 

 presence in the bread unpleasant is, that it is the indi- 

 cation of organic matters, evidently proceeding from 

 suspicious sources : from domestic waters for instance, 

 or the infiltrations that escape from the 60,000 privies 

 sunk below the soil. We must not forget, also, that 

 every year, by the rising of the Seine, the subterranean 

 inundations put in communication the inferior with the 

 upper strata of the soil, in the latter of which are the 

 receptacles of the night-soil, &c., and that the waters in 

 washing the soil convey, in what they draw, spores of 

 cryptogamic vegetation — those mouldinesses always 

 hurtful, and so much more to be dreaded that their 

 organism, apparently so frail, resists nevertheless the 

 temperature of the oven in baking bread, as laid down 

 by M. Payen, and more recently by M. Pagiale. 



In a memoir read before the Academy in 1852, I have 

 already spoken of the disgust inspired by the well water 

 when we know, and no one is now ignorant of it, that 

 they are employed in the bakeries. Already, if I am 

 well informed, the administration of the hospitals have 



made arrangements for procuring the water of the Seine 

 to the bakehouse of Scipion. This is undoubtedly an 

 example that will be imitated ; for we cannot compre- 

 hend why, at Paris, they should persist in preparing 

 bread with impure water. 



From the whole of these investigations we may justly 

 conclude that with regard to the fertilizing principles 

 they bring to the earth by irrigation or absorption, the 

 waters which circulate on the surface, or at a slight depth, 

 act much more by the saltpetre than by the ammoniacs 

 which are found in them. In my paper ou the ammoniacs 

 of the waters I have shown that river water rarely holds 

 above 0.2 gr. and spring water 0.02 of alkali per cubic 

 metre ; now the results hitherto obtained indicate in a 

 cubic metre of the same waters the equivalent of 6 to 

 7 gr. of nitrate of potash, answering, as azoteous manure, 

 to 1.10 gr. of ammoniac. These numbers are very 

 nearly the same as those deduced by M. Bineau from 

 his chemical studies on the waters of the basin of the 

 Rhone. 



The geological constitution of a country has likewise 

 the most decided influence on the proportion of salt- 

 petre. This influence, which is stated by M. Bineau, is 

 above all revealed in the course of this work. Thus, in 

 the lakes hollowed in syenite the waters exhibited only 

 traces scarcely appreciable of nitre ; those which proceed 

 from the red or quartzose sandstone of the Vosges appear 

 not to have more than 0.5 gr. per cubic metre ; whilst 

 in the calcareous lands, as they belong to the trias, to 

 the jurassique country, to the cretaceous group, or to 

 the tertiary deposits above the chalk, the spring and 

 river waters have furnished the equivalent of 15 gr. per 

 cubic metre of nitrate of potash, and the proportion has 

 varied from 6 to 62 grammes. 



If in the springs and rivers there is generally more of 

 nitrates than of ammonia, the contrary seems to exist in 

 rain and snow water and dew. 



From experiments continued for six months in 1852, 

 we established that meteoric water, collected from a 

 great distance from inhabited places, contain on an 

 average 0.74 mgr. of ammonia per litre. Since then 

 Messrs. Lawes and Gilbert have found a number nearly 

 similar, by observations during a whole year, at Rot- 

 hams tead. 



In the summer and autumn of 1856 I have examined 

 ninety samples of rain collected at Liebfrauenberg. la 

 seventy- two of those waters it was possible to detect the 

 nitrates, which agrees with what M. Barral has stated ; 

 and the quantitative results to which I have arrived, 

 although leaving perhaps something to wish for, never- 

 theless authorise me in believing that rain, when it falls 

 in the middle of fields in the proximity of extensive 

 forests, contains much less nitric acid than ammonia. 



BOUSSINGAULT, 



Member of the Academy of Sciences, and of 

 the Central Society of Agriculture, 



THE ADVANTAGES OE A DAILY REGISTER OF THE RAIN-EALL THROUGHOUT 

 THE UNITED KINGDOM, AND THE BEST MEANS OF OBTAINING IT. 



That the advantages of an accurate register of the 

 rain-fall would be abstactedly useful, no one would 

 for a moment dispute. We would even say that i'or 

 certain practical purposes — such, for instance, the use 

 of water-courses as a motive-power, the regulation 

 of flood-gates in flat districts exposed to inundations, 

 or even for the purposes of irrigating and warping — 

 such an accurate register as Mr, Denton advocates 

 is indispensable, if certain success be aimed at, and 

 nothing left to hazardous and reckless speculation ; 



but we certainly difier from him, when he attempts 

 to attach to this accurate and universal register a 

 necessary action and influence over the drainage of land. 

 It is evident that drains are not meant for a constant 

 and iicv.:-^ .'. i.^ action. Their use is to discharge 

 water when there is an excess of water to discharge. 

 Where much rain falls upon the surface they underlie, 

 their action is more frequent than in districts where a 

 less quantity of water falls from above ; but on account 

 of that more frequent use, provided the outlet they 



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