Xi 
On the reading of Mr. Henwood’s Paper on Detrital Tin Ore, 
Dr. BARHAM remarked that the record it contained, together with 
others brought before the Institution some time since, appeared 
to be confirmatory of an opinion that formerly the proportion of 
stream-tin from Devonshire, as compared with Cornwall, was 
much greater than in recent times ; notices had also been received 
of some remains of supposed ancient tin-works west of Dartmoor. 
—Mr. HENwoop remembered that Sir Edward Smirke produced 
here some accounts which led to the same conclusion. 
With reference to a part of Sir John Maclean’s Paper on the 
ancient Tin Trade of Cornwall, Mr. HENwWoopD wished to make a 
remark, which he would endeavour at some future time to expand. 
In addition, to the duty of 1s. 63d. per 112lbs. in Devon, and 4s. 
per 120lbs. in Cornwall, the Duchy also received other sums which 
were charged as for “great pieces,’ and which sums he had no 
doubt were charged as a fine on those persons who sent blocks that 
were not admissible. There was also a charge in respect of ‘“ white 
rent,” and which he was unable to explain. 
Dr. BArHAmM asked if there was any evidence as to the weight 
of blocks at that time. The weight of most_of the Jews’ House 
blocks in the county had been ascertained. 
Mr. Henwoop did not think there was anything like either a 
prevalent, or average, weight of the masses of Jews’-house tin ; 
but, generally speaking, they were of very good quality indeed. 
Some time since, a specimen of Jews’-house tin was given him by 
Mr. Petherick, of St. Austell; it was found near that town; and 
he believed he had presented it to this Museum in the donor’s 
name. In it there were particles of tin ore and charcoal agglom- 
erated in a cement of metallic tin; shewing that the process had 
been discontinued whilst only part of the ore had been converted 
into metal. 
Dr. BARHAM said it would be recollected that Mr. Poole, of 
the British Museum, had ascertained that the unique block in 
this Museum, on which Sir Henry James had written, and which 
had been called the Astragalus of Tin, from its resemblance to the 
form of the ancient blocks described by Diodorus Siculus, weighs 
158lbs. and that our fine specimen of Jews’-house tin weighs 394 
lbs., exactly one fourth of the former, which corresponds with two 
talents of the later AXigineton or Commercial Attic scale; and he 
drew an inference from this conformity of weights in favour of 
the story of Phcenician trade with Britain. With reference to the 
particles mentioned by Mr. Henwood, it occurred to him that 
possibly the ore was smelted into casual moulds of clay, and that 
thus loose particles got attached to the bottom of the smelted 
metal. 
