OF THE SEVEN WELLS. 



Ill 



ble to obtain, for any length of time, good water from the 

 wells sunk within the polluted area, however good the water 

 may be when first drawn. From this the natural and only 

 sound inference to be deduced seems to us to be, that it will 

 be necessary for Government to look for water beyond this 

 polluted area : and if the supply be required only for the 

 Fort, probably the simple apparatus now in use at the so- 

 called ' Seven Wells' would be sufficient, supposing that the 

 wells be sunk a mile or thereabouts beyond the limit of dense 

 population. 



Note on the Magnetic Oxide of Iron. 



As this substance has lately been brought prominently 

 before the public, and has been much lauded on account of 

 its special action in purifying waters ; and as, moreover, a 

 Committee of the National Exhibition have lent the sanc- 

 tion of their names to it, as a voucher for the above men- 

 tioned special quality, it appears almost necessary in a paper 

 of this kind to offer a few words respecting it, particularly 

 in reference to the two questions of Natural and Artificial 

 supply. 



Magnetic Oxide of Iron, it is well known, is a natural 

 product found largely in certain localities ; but it is very 

 questionable whether it can every where be so readily 

 obtained, and in such quantity, as to make its use practica- 

 ble on a large scale. All the reliable information on this 

 head, that has been procurable, will be given at the end 

 of this note; and if it should turn out that this pro- 

 duct can only be had here and there, and in places at 

 considerable distances from those situations, whereat filter 

 beds are to be made : — then, the only resource will be the 

 artificial product— and in order to afford a clear view of the 

 practicability of resorting to it. the shortest way will be to 



