Intelligence and Miscellaneous Articles, 395 



turers have long used similar apparatus for obtaining this acid, and 

 particularly the vessels employed in the preparation of ammonia, 

 M. Boutigny has thought it proper to mention the above result, 

 which may be useful to certain persons, as even the most recent 

 chemical works recommend the preparation of sulphurous acid in 

 glass or earthen vessels, which are always very expensive, and dan- 

 gerous on account of their great fragility. — Ibid. 



ON THE ALTERATION WHICH WELL-WATER UNDERGOES. 

 BY M. C. BLONDEAU. 



The analysis which the author has performed on the water of a 

 great number of the wells of Rhodez, has led him to adopt the fol- 

 lowing conclusions :-— 



1. Well-water may be altered by two causes ; by the presence of 

 mineral salts held in solution, and by that of animal matters. 



2. The mineral substances which occur in solution are silica, alu- 

 mina, carbonates and phosphates of lime and magnesia, potash-alum, 

 chlorides of calcium, magnesium and sodium, w T ith nitrates of the 

 same bases. These different substances are not hurtful to the animal 

 ceconomy when they exist only in small quantity. Well-water, [of 

 which a litre ? J contains only 4 to 5 centigrammes of these sub- 

 stances in solution, may be employed for all domestic uses, provided 

 it does not contain too large a proportion of animal matter. 



3. Water, of which a litre contains one gramme of the above- 

 mentioned substances, may still be good for drinking ; but it is not 

 fit for cooking vegetables or washing linen when it contains 0*1 grm. 

 of lime or magnesia. 



4. Water, of which a litre contains 0*1 grm. of lime or of mag- 

 nesia, and 0*1 grm. of organic matter, is improper for any domestic 

 use. 



5. It is of the utmost importance to state the existence and de- 

 termine the quantity of animal matter held in solution in waters ; 

 for if they exceed the limits above-stated, they act disastrously on 

 the ceconomy, and may occasion dysentery, and various maladies 

 which appear to be contagious because the whole population acquire 

 the seeds at the same sources. 



6. The presence of magnesia in drinkable waters does not produce 

 so hurtful an action as supposed by some persons. The well-water 

 of Rhodez contains on an average five times as much magnesia as 

 the waters of the valley of the Iser, anatysed by M. Granger ; and 

 yet endemic diseases, as goitre and cretinism, are entirely unknown 

 in the chief town of Aveyron. 



7 . The water of certain wells possesses a very disagreeable earthy 

 taste ; this taste is derived from alumina held in solution by carbonic 

 acid. It is observed that those well-waters which contain most of 

 this base have the strongest earthy flavour. 



8. It results from these experiments, that a classification of drink- 

 able waters, based on the relations which exist between the sulphates 

 and the chlorides, must be a defective one ; for this relation varies 



