228 TRANSACTIONS OF THE PLYMOUTH INSTITUTION. 
On the Gobbett site are heaps of broken-up slag, which still 
further confirms this opinion. The readiest and most effective 
plan for dealing with slag is of course by stamping, and the use 
of primitive mortars for this purpose tends to show that they 
must have been in use before stamps were generally employed, 
thus giving the blowing-house ruins possessing them a probable 
antiquity of at least three centuries. They may be much more 
ancient than this, but unfortunately there are no data at present 
available to guide the enquirer. 
Whilst at Eedruth, on the 14th of February last, the writer was 
informed by Mr. A. H. J enkin that on the same day two granite 
stones, with eggcup-shaped cavities, had been laid bare in digging 
the ground in front of the new hospital, which is situated on an 
eminence known as Blowing-house Hill. It is interesting to note 
that the two cavities, one in each stone, are similar to those found 
on Dartmoor. The cavities at Eedruth are circular, the diameter 
being eight to nine inches, with a depth of about six. A layer of 
charcoal was found near the stones, which were nearly two feet 
under the present surface of the field. This interesting find fixes 
the actual site of the blowing-house, which has given its name for 
an unknown period to the district. 
What has been previously described under the name of the 
Har Tor blowing-house is situated high up on the head waters of 
the Meavy, and reference has also been made to the extensive 
streaming operations in the neighbourhood of this ruin. These 
stream works continue right down the valley to Sheepstor Bridge, 
with occasional traces much further down the river. The small 
tributary streams running into the river also bear traces of old 
surface mining operations. 
There is a striking example of this at Hoo Meavy. Here the 
operations must have been extensive, for the cuttings are deep and 
wide, and the mounds of debris large. From the hamlet to the 
common close to Green will, the artificial ravine made by the " old 
men " has been planted with trees which are of considerable size, 
and form a delightfully-shady and picturesque road of about a 
quarter of a mile in length. These workings run across to 
Cadaford Bridge, a distance of about two miles. On the other side 
of the river they are continued up to and beyond Clearbrook. No 
blowing-house remains are now visible. If any existed they have 
been doubtless used in the construction of hedges or houses. 
