234 ANNUAL OF SCIENTIFIC DISCOVERY. 



mineralogist should be able to account for the occurrence of every substance 

 which conies under his notice. This is more especially the case when the sub- 

 stance is of an organic nature, and in general we have little difficulty in satis- 

 factorily explaining even such occurrences. The mineral Humboldtine, for in- 

 stance, being found either imbedded in lignite, or associated with decomposing 

 succulent plants, leaves no room for doubting that, as it is organic in its matrix, 

 so also it is organic in its origin. I am afraid, however, that our ingenuity 

 will be taxed rather severely to account for the three other oxalates which 

 we are now acquainted with, two of these having been found deep in the 

 womb of the earth, associated with a metallic lode. I think there can be 

 little question that they are of secondary formation, having resulted in some 

 way or other from the operations connected with the working of the mine; 

 but I profess to be perfectly unable to offer any explanation which appears 

 even to myself to be satisfactory. One theory has been brought forward a 

 theory which I can not but dissent from ; it is that the minerals were origin- 

 ally bi-carbonates that metallic potassium having been brought into contact 

 with them, an atom of oxygen was abstracted, the result being necessarily ox- 

 alates. This does not appear satisfactory ; neither bi-carbonate of lime or of 

 potash have yet been found in nature ; and I can not place myself among 

 those who, whenever they wish to account for volcanic action, or to get out 

 of any difficulty, call in the aid of metallic potassium. I am very far from 

 thinking that no satisfactory theory can be brought forward, but I am content 

 for the present to look upon the occurrence of these oxalates as one of many 

 proofs that as yet we know but too little of the operations carried on in 

 nature's laboratory. The first of these minerals has been named Conistonite, 

 from the locality ; and the second Heddlite, after the analyst. 



ON THE COMPOSITION AND PREPARATION OF WRITING 



INKS. 



The following is an abstract of a paper recently read before the Society of 

 Arts, Edinburg, by Dr. J. Stark : 



The author stated that in 1842 he commenced a series of experiments on 

 writing inks, and up to this date had manufactured 229 different inks, and 

 had tested the durability of writings made with these on all kinds of paper. 

 As the result of his experiments, he showed that the browning and fading of 

 inks resulted from many causes, but in ordinary inks chiefly from the iron be- 

 coming peroxygenated and separating as a heavy precipitate. Many inks, 

 therefore, when fresh made, yielded durable writings ; but when the ink be- 

 came old, the tannogallate of iron separated, and the durability of the ink was 

 destroyed. From a numerous set of experiments, the author showed that no 

 salt of iron and no preparation of iron equalled the common sulphate of iron 

 that is, the commercial copperas for the purpose of ink making ; and that 

 even the addition of any persalt, such as the nitrate or chloride of iron, though 

 it improved the present color of the ink, deteriorated its durability. The 

 author failed to procure a persistent black ink from manganese, or other metal 

 or metallic salt. The author exhibited a series of 18 inks which had either 



