Scientific Intelligence. 
al^um.. The specific gravity is 1.35. 
suits of Dr Ure’s analysis : 
The followin; 
Sulphuric acid, 
34.00 
Alumina, 
10.75 
Soda, 
6.48 
Wdter of crystallization. 
49.00 
100.23 
Dr Ure is of opinion that this salt is well adapted for certain 
purposes in calico-printing, by its remarkable solubility in water. 
By distilling a portion of its solution off lime, he ascertained 
that it contains no ammonia. 
17. Melanie Acid in Blade Urine.-^J)v Marcet has described, 
in the 12th volume of the Medico-Chirurgical Transactions, a sin- 
gular variety of urine, which turned black soon after it was dis- 
charged ; and he has given the following notice of its chemical 
properties, as communicated to him by Dr Prout : — “ The resi- 
duum obtained from this urine by evaporation, not only does not 
contain any lithic acid, but no urea can be detected in it. Al- 
though the addition of dilute acids produced no immediate 
change of colour in the urine ; yet, on standing for some time, 
a black precipitate slowly subsided, leaving the supernatant fluid 
transparent, and but slightly coloured. The black precipitate thus 
obtained, was found to be nearly insoluble either in water or al- 
cohol, whether hot or cold It readily dissolved in cold concen- 
trated sulphuric and nitric acid, forming a deep brownish-^black 
solution ; but, on diluting the acids with water, the black sub- 
stance appeared to be again precipitated unaltered. These acids, 
however, by the assistance of heat, apparently decomposed it. 
The black substance readily dissolved in the fixed alkalies, and 
in the alkaline sub-carbonates, forming very dark solutions. The 
addition of water did not affect these solutions ; but acids repre- 
cipitated the substance apparently unchanged. When ammonia 
was employed as the solvent, and the excess expelled by evapo- 
ration to dryness, a black or deep brown residuum was obtain- 
ed, which appeared to be a compound of the black substance 
with ammonia, and possessed the following properties. It was 
very soluble in water ; and, on being heated with caustic potash, 
it gave off the smell of ammonia. The black compound, how- 
ever, did not appear to have any tendency to assume the crystal- 
line form. From the solutions of this compound in water, mru 
