308 
Proceedings of Royal Society of Edinhurgli. [april 16 , 
= A(0 3 4 5) + A(0 2 4 6) - A(1 2 3 6) - A(1 2 4 5) 
+ A(1 245) + A(0156)-A(1245) 
+ A(1 2 3 6) + A(1 2 4 5) - A(0 1 5 6) + A(0 2 4 6) - A(0 3 4 5) 
=..2A(0 2 4 6)-^C| 
- 2A(0 12 3). 
Adding to this 2>\a%'^c‘^ al>c \ which equals -3A(0123) we have the 
original given alternant equal to 
- A(0 1 2 3) 
as it should be. 
5. Quaternion Note. By Professor Tait. 
6. Exhibition of Specimens. 
Dr Murray, by permission of the Meeting, exhibited specimens 
of Eggs of Cod and Haddock, taken from the surface of the sea near 
the Isle of May. 
Monday, '7th May 1888. 
Loed M^LAEEN, Vice-President, in the Chair. 
The following Communications were read : — 
1. On the Secretion of Lime by Animals. By Robert 
Irvine, F.C.S., and Dr G. Sims Woodhead, M.D. 
The enormous amount and peculiar character of the deposits of 
carbonate of lime, found in all parts of the globe, give the question 
of the formation of these deposits a peculiar interest, consisting, as 
these deposits do, of fossilised remains of lime-secreting animals, 
and bearing witness in themselves as to their origin. It is beyond 
question that the great mass of carbonate of lime found in the later 
geological epochs has, primarily, been absorbed by the marine 
fauna and flora from the ocean, and secreted by them in the form 
of coral, shells, or calcareous plants. From this may be realised the 
important function which lime salts play in respect to the economy 
of marine life. 
