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measures. It also seems probable that the bed in which the 
fossils are met with at Ashton Moss pit is the same, or one 
lying near to it, as that discovered by Prof. Green, above the 
Big Mine of Dukinfield, and that the strata seen in the Tame 
lie pretty regular between the two places, and have not 
been much disturbed by faults. 
“ Some endeavours to ascertain the nature of the insolu- 
ble form of Soda existing in the residue left on Causticising 
Sodium Carbonate with Lime/’ by Watson Smith, F.C.S., 
Assistant Lecturer on Chemistry in the Owens College, and 
Mr. W. T. Liddle. 
In the following are given the results of an inquiry (yet 
in progress), which were obtained towards the close of 
last session, in the Laboratory of Owens College, by Mr. 
W. T. Liddle in conjunction with myself, and with the occa- 
sional co-operation of Mr. H. Bimmer. The present inquiry 
was the final step after a series of exercises in the technical 
examination of some alkali products by the two gentlemen 
named, kindly furnished by Messrs. Gaskell, Deakin, & Co. 
Hargreaves (Chem. News, 387) and Kynaston (Chem. 
Soc. J., 11, 135) have noticed the occurrence of soda in an 
insoluble form in the crude soda (black ash) of the alkali 
works, but they only speak of alumino-silicates and silicates 
of sodium, and in these early papers mentioned don’t appear 
to imagine any other insoluble compound present in which 
soda may be practically lost to the manufacturer. 
Dr. G. B. A. Wright published a paper (appearing in 
Journ. Chem. Soc., year 1867, p. 407) in which he distinctly 
shows (1) that soda in an insoluble form does exist in black 
ash treated with water, in process of lixiviation, and (2) that 
though it may partly exist as alumino-silicate, yet undoubt- 
edly it exists in some other form, and most probably as a 
double sodium calcium carbonate. 
To show the importance to the soda manufacturer of this 
