Details of Borings in Search of Fresh Water. 
Iff? 
colour, which M. Chapta] remedied by means of a little glue*, which precipitated the 
tannin ; perhaps observations like these may be frequent, but it is plain, that their ap- 
plication is notgenerai. Oxygen, he thought, generally was necessary as a constituent 
of colouring matter, but he also thought, that there were exceptions, and although he 
knew that the various changes and destruction of colour of which indigo is sus. 
ceptible, depended on the proportion or total abstraction of its oxygen, he yet seems 
not to have had the slightest idea of referring the change and destruction of colour, 
in other colouring matter, to the same cause. Ho ascribes bleaching by exposure to 
the sun to disoxygenation, but the bran liquor produces the same effect, and is used 
with the same intention in clearing the grounds of printed goods ; and though when 
used in the bath employed for dying those goods, the grounds are much less disco- 
loured than they otherwise would he, yet it seems never to have occurred to him that 
those effects proceeded from the same cause -f- ; on the contrary, he concludes that the 
bran bleaches the grounds by superior affinity, by attracting the colouring matter 
from the cotton^. 
Should the opinions I have hazarded, which have been hastily' put together, and which 
circumstances unnecessary to mention prevent me from revising, attract to the sub • 
ject any one more capable than myself to do it justice ; I am not, I confess, without 
hopes, that the prosecution of the inquiry may be productive of some utility, in w hich 
case the end I proposed to myself, on venturing to put them on paper, will have been 
very completely answered. E. M. 
II Details of several Borings made in Calcutta, in search of a 
Spring of Fresh Water. 
To the Editor of the “ Gleanings.” 
Sir, 
I have now the pleasure to forward the abstracts of the Borings promised in my 
former communication. 
ft may not be unnecessary to mention, that the water of several wells, from 20 to 
40 feet deep, having all proved so brackish as to be unlit for drinking, the borings 
were undertaken to ascertain whether fresh springs were to be met with at a greater 
depth ; and the nature of the intervening strata. The borings were all made within 
a limited extent and adjoining to the wells ; and the gentleman who conducted the 
operations was so satisfied with their results, that he was preparing to sink a well 
of masonry on the line of Section No. 5. when ill health compelled him to leave 
the country. 
He was' apparently unacquainted with the method since so extensively adopted 
of lining the hole made by the auger with a metal pipe, and thus superseding the 
necessity of sinking a well below the level to which the springs will rise of tlieirown 
accord. 
*1. E. disoxygenated the colouring matter- It is worthy of remark, that dyeing drugs 
relatively to each other are oxygenating and disoxygenating, the lighter colours are 
generally disoxygenating towards the darker ; the most disoxygenating, according 
to my experience, is turmeric. A dissertation, however, on this subject would be ne- 
cessary, thoroughly and satisfactorily to explain it. 
t Bran liquor was sou r and oxygen was the sour principle ; therefore, I suppose 
it was concluded, that acids would afford to part with oxygen, and consequently were 
deemed oxygenating; but from whatever cause it proceeded, it is certain that chemis- 
try held it as a sort of a fundamental principle, that acids were oxygenating, and 
alkalis disoxygenating ; though, with regard to colouring matter, the reverse is uni. 
versally the case, and innumerable chemical phenomena are wholly inexplicable 
u pon this assumption. 
t It is remarkable that although solution of tin is known to he generally disoxy- 
genating, and although Dr. Bancroft himself successfully used it with this intention 
to dissolve indigo, yet that the effect produced by it on those colouring matters em- 
ployed to dye scarlet was never attributed by Dr. Bancroft to this property ; hut 
to a peculiar chemical action, without any attempt to explain the nature of that 
action. 
