Mr Hunter's Notes 07i a Ncio Compcnind of Uranium. 295 



is curious on the subject, I shall be glad to show a specimen 

 at another meeting. 



Uranium is not very extensively used in the arts and 

 manufactures, and yet where it is employed it is not easily — 

 if it can be at all — replaced by any substitute. In Germany 

 a pigment containing copper and uranium is used by paper- 

 hanging manufacturers ; while in this and in other countries 

 uranium does good service in enamel painting ; and in glass- 

 staining, which is not an unimportant trade now-a-days, it is 

 questionable if the same fine tints can be produced from any 

 other material — the protoxide imparting a deep black, and 

 the sesquioxide a beautifully pale yellow colour. 



Its tinctorical power, if I may use the term, is also of 

 service in the porcelain factory, where a mixture of pitch- 

 blende is employed in the production of the deep black colour 

 under the glaze. Then in dyeing also, and in photography, 

 uranium salts are more or less called into requisition. 



In alluding to uranite, I mentioned that in that ore 

 uranium was in combination with phosphoric acid, and it is 

 somewhat strange that in the estimation of that very acid 

 uranium should be of the most importance to the analytical 

 chemist. In all agricultural countries, and especially old 

 countries such as our own, where high rents are the order of 

 the day, farmers are compelled to purchase large quantities of 

 artificial manures, one of the chief constituents of these being 

 phosphoric acid. In the purchase, then, of these costly 

 manures, analytical chemists are largely employed for deter- 

 mining, along with the other constituents of course, this 

 valuable phosphoric acid; and, strange though it may 

 seem to you, there are some men in this country calling 

 themselves chemists who employ processes for the estimation 

 of this acid which are as erroneous as they are antiquated. 

 This may appear to you a small matter, but I may help you 

 to alter your opinion a little. By the processes to which I 

 refer, an error of 1 to 10 per cent, will most probably occur. 

 Now suppose that 60,000 tons are sold, and that there is an 

 error of even 3 per cent, in the phosphoric acid estimation, 

 that may represent a sum of £18,000, which is simply a loss 

 to the country; and when I tell you that Newcastle alone 



