2fi4 On Improvements in Black Writing Ink. 



which way both their colour and their consistence might be mi- 

 nutely ascertained. A third method was to add together the 

 respective infusions, and the solutions of the sulphate of iron, in 

 a very diluted state, by which I was enabled to form a more 

 correct comparison of the quantity, and of the state of the colour- 

 ing matter, and of the degree of its solubility. 



The practical conclusions that I think myself warranted in 

 drawing from these experiments, are as follows : — In order to 

 procure an ink which may be little disposed either to mould or 

 to deposit its contents, and which, at the same time, may possess 

 a deep black colour, not liable to fade, the galls should be mace- 

 rated for some hours in hot water, and the fluid be filtered; it 

 should then be exposed for about sixteen days to a warm at- 

 mosphere, when any mould which may have been produced must 

 be removed. A solution of sulphate of iron is to be employed, 

 which has also been exposed for some time to the atmosphere, 

 and which, consequently, contains a certain quantity of the red 

 oxide of iron diffused through it. I should recommend the in- 

 fusion of galls to be made of considerably greater strength than 

 is generally directed ; and I believe that an ink, formed in this 

 manner, \vill not necessarily require the addition of any mucila- 

 ginous substance to render it of a proper consistence. 



I have only further to add, that one of the best substances for 

 diluting ink, if it be, in the first instance, too thick for use, or 

 afterwards becomes so by evaporation, is a strong decoction of 

 coffee, which appears in no respect to promote the decomposition 

 of the ink, while it improves its colour, and gives it an additional 

 lustre. — Transactions of the Society of Arts of London, vol. xlvii. 



Additions to the Natural History of British Animals. By John 

 Coldstream, M. D., M. W. S., &c. (Communicated by the 

 Author). 



kjorvna Sqvamata, (Fleming, Brit. An. 553). — The tentacula 

 vary in number from 5 to 25. There are generally five bo- 

 tryoidal groups of vesicles, sometimes only one. After having 

 been kept in small vessels of sea-water for some hours, without 

 renewal of the water, some of the animals protrude the inner 

 surface of the mouth, so as to present a convex disc, with the 



