6 
From the character of the fossil organic remains and the 
nature of the strata he was led to believe that the coal field 
of Puertollano was of the same geological age as our true 
English coal measures. 
Mr. M. M. Pattison Muir, F.RS.E. ; exhibited and gave 
a description of a modified form of Hofmann’s Apparatus 
for Determining Vapour Densities. 
“Note on an Edible Clay from New Zealand/’ by M. M. 
Pattison Muir, F.R.S.E. 
I lately received from my friend Mr. P. E. Day, M.A., a 
small specimen of a clay which is greedily eaten by the 
sheep in a certain district in New Zealand. 
The clay was brought by Mr. Day from Simon’s Pass Sta- 
tion, Mackenzie country, South Island. It there forms a range 
of low bare hills: the sheep (merino sheep) eat very consi- 
derable quantities of the clay without appearing to be any 
the worse for it. So far as Mr. Day could learn the clay 
eating is confined to this particular part of the Islands. It 
is supposed by the shepherds that the clay must contain 
salt, and that it is to supply the deficiency of this article of 
food that the sheep resort to the earth. The analysis shows 
that very probably the shepherds are right, although one 
would suppose that to consume so much silica and alumina 
for the sake of the small proportion of salt was hardly an 
economical proceeding on the part of the sheep. 
The alkali was determined by Lawrence Smith’s process 
of fusion with calcium carbonate and ammonium chloride. 
The water was determined by heating in a stream of dry 
air and direct weighing of the moisture expelled : the organic 
matter, by noting the difference between the amount of 
water thus obtained and the total loss suffered on ignition. 
Silica = 61*25 
Alumina ~ 17*97 
