OF PYRITES AND GYPSUM. 3I3 



"but likewise where it is loamy or clavie ; and this year 1728, I did not only 

 <^ather them from there myself, but did likewise see divers Boys gathering them 

 €ven at the Place where the Clitf is highest and most loamy ; and as every Tide 

 washeth away some of the looser Earth which falleth down from the Cavities of 

 the Clif, those Stones being most ponderous are there left ; and as soon as the 

 y^ide permits they busily gather them.'' 



It is interesting to learn from Dale that " The Pyvita; oi Essex, 

 Kent, etc., yield upon Trial, a small quantity of Gold and Silver, 

 and some of them a little Coppery 



Referring to the nodules of pyrites in the cliffs of London 

 Clay near Waiton-on-the-Naze, Mr. Whitaker, writing in 1877, 

 tells us that they were then still collected on the beach for the 

 manufacture of copperas to the extent of about 150 tons a 

 year.'-* 



The term " copperas " naturally suggests that the substance 

 so called contains copper, and this no doubt was originally the 

 case. But the word gradually acquired an extended meaning, 

 and, instead of being limited to copper sulphate, came to be 

 applied also to the corresponding salts of other metals. Hence 

 we recognise not only " blue copperas," or copper sulphate, but 

 ■*' green copperas," or iron sulphate, and *' white copperas," or 

 zinc sulphate — three salts known also respectively as blue 

 vitriol, green vitriol, and white vitriol. But the strangest thing 

 about the word " copperas " is tliat in the course of its history it 

 has come to be almost limited to the iron-salt, so that the other 

 compounds just mentioned are rarely called copperas at the 

 present day. If we use the word " copperas " without any 

 ■qualification we invariably mean sulphate of iron : in other words 

 our copperas contains no copper. In Dr. Murray's great 

 National Dictionary it is pointed out [suh voce) that the extension 

 of meaning took place anterior to the appearance of the word in 

 English, for iron sulphate was included under the Greek word 

 XaA/cai/^oi/ and the Latin chalcanihum. In the explanation 

 of the term, however, there is a slight error, for reference is made 

 to " the dissolving of iron by a solution of green copperas with 

 deposition of its copper " — a passage in which the word " green " 

 should obviously be " blue," for it must be the copper sulphate 

 and not the iron-salt that is meant. 



With regard then to the old copperas-houses of Walton, let 



9 The Geology of the Eastern End of Essex (Walton Naze and Harwich)^ Memoirs of the 

 •Geological Survey. 1887, p. 8, 



