11 
Monday , 17 th January 1881. page 
Preliminary Report on the Tunicata of the “ Challenger” 
Expedition. Part III. By W. A. Herdman, D.Sc., . 52 
On the Histology of the Pedicellariae and the Muscles in 
Echinus sphcera , Eorbes. By Mr Patrick Geddes, 
F.R.S.E., Lecturer on Zoology in the School of Medi- 
cine, Edinburgh, and Mr Prank E. Beddard, B.A., 
Assistant-Demonstrator of Zoology, Oxford, . . 88 
Additional Note on an Ultra- N eptunian Planet. By Pro- 
fessor George Forbes, . . . .89 
On some Effects of Rotation in Liquid Jets. By Professor 
Tait, ....... 94 
Note on the Influence of Temperature-Change of Conduc- 
tivity on the Conduction of Heat in Solids. By Pro- 
fessor Tait, . . . . . .94 
Monday , 7th February 1881. 
Obituary Notices of Fellows who died in the course of 
Session 1880-81 : — Mr Thomas Key, Dr William 
Lassell, Mr Maurice Lothian, Mr Mungo Ponton, Mr 
Thomas Knox, the Hon. Lord Ormidale, Professor 
Sharpey, . . . . ■ . 95-116 
On a Simple and Accurate Method of determining the 
Longitude of a Place by a Single Observer, without the 
aid of any instrument for measuring time. By Pro- 
fessor George Forbes, . . * . .117 
Stilbite, from Kerguelen’s Island. By A. Liversidge, Assoc. 
Royal School of Mines, Professor of Geology and 
Mineralogy, University of Sydney. Communicated by 
Mr J. Y. Buchanan, . . . . .117 
On a Simple Form of Selenium Cell, and Experiments there- 
with. By Professor James Blyth, . . .119 
Dust, Fogs, and Clouds. By Mr John Aitken, . .122 
Note on Thermal Conductivity, and on the Effects of Tem- 
perature-Changes of Specific Heat and Conductivity on 
the Propagation of Plane Heat Waves. By Professor 
Tait, . . . . . . 126 
Note on a Simple Method of showing the Diminution of Sur- 
face Tension in Water by Heat. By Professor Tait, . 131 
On the Cell-Walls of Hepatic Cells. By John Berry Hay- 
craft, M.B., B.Sc., F.R.S.E., Senior Demonstrator of 
Physiology in the University of Edinburgh, . . 131 
Monday, 2\st February 1881. 
Effects of Strain on Electric Conductivity. By M. August 
Witkowski. Communicated by Sir William Thomson, 135 
On the Effect of Moistening with Water the opposed Metallic 
Surfaces in a Yolta-Condenser, and of substituting a 
Water- Arc for a Metallic- Arc in the Determining Con- 
tact. By Sir William Thomson, . . .135 
On Vortex Sponge. By the Same, . . .135 
For continuation of Contents , see pp. 3 and 4 of Cover. 
