21 
_ Pyrameis atalanta. A description of the colour variation is here given :— 
_ Measurements same as in the type. Front wings: Costa and hind margins 
black, diffused with brown (blue spots entirely absent). Central area of orange 
red, diffused with sooty-brown, with one black spot instead of three. Hind 
4 wings: Blue spots on hind margin, as in the type, or nearly so. Subterminal 
band of orange red, almost hidden with diffusion of sooty-brown. Under 
surface generally diffused with sooty-brown (nearly black).’’ The specimen is 
in the possession of the collector. 
GEOLOGICAL SECTION. 
Two meetings have been held during the Session. At the first Mr. G. A. 
Dunlop, of the Warrington Museum, gave an illustrated lecture on ‘‘ The 
Changes in the Wirral Coast’”’ to an excellent audience. The lecturer, after 
dealing with Britain of pre-glacial and glacial times, took as his starting point 
the later pleistocene changes which resulted in the relative Wirral coast lines 
of to-day. The considerable coastal changes through subsidence and erosion 
from Roman times almost to the present day were traced out by maps and 
records. A survey of the submerged forest at Dove Point, and a recital of 
the many objects of antiquarian interest found on or near its site, concluded 
an instructive lecture. 
; At the second meeting Mr. T. Arthur Acton, F.S.A., of Wrexham, lectured 
on ‘ The Geology and Economic Value of the Boulder Clay in North Wales and 
_ Cheshire, especially as regards the manufacture of Roman Pottery.’’ The 
“many lantern illustrations of the results of the recent Holt excavations, for 
_ which, by the way, the lecturer had been mainly responsible, showing Roman 
_ kilns and roofing and other tiles of the XXth Legion, were viewed with much 
appreciation by Mr. Acton’s interested audience. 
NATURAL PHILOSOPHY SECTION. 
BACTERISED PEAT. 
By J. Barrstow, Esq., F.C.S. 
__ The lecturer pointed out that peat was the medium selected by Professor 
30ttomley for carrying fertilising bacteria which transformed the insoluble 
humic acid of peat into soluble humates, hence Professor Bottomley had given 
to bacterised peat the name of humogen. Professor Bottomley claimed that 
: humogen was superior to all other forms of nitrogenous manure, and he had 
given some remarkable examples in proof of his contention. Generally ‘speak- 
g the proofs offered by Professor Bottomley were perhaps too few from which 
to draw such important conclusions, but they were highly suggestive, and every 
_ year this difficulty would decrease. Exactly how Professor Bottomley inoculated 
the peat was not clear, and had not yet been divulged, but it was known that 
the action depended upon two groups of bacteria, the first being anaerobic, 
working only in the absence of oxygen, and the second aerobic, working in 
the presence of oxygen. When the operation is complete, the bacteria are 
destroyed by heat, and the peaty material is rendered sterile. Afterwards 
sterile material is inoculated with nitrogen fixing organisms, and the 
erial becomes a valuable plant food. The most important of the nitrogen 
{ organisms it was stated, were the azotobacter chroococium, and the 
us radicicola, and these grew very rapidly under favourable conditions; 
from depredations of larger organisms, and energetically stimulated the 
owth of plants. In Professor Bottomley’s method, these larger and preying 
ganisms were destroyed, and the bacteria could then exercise their beneficent 
ers to the greatest extent. In the course of the lecture, the origin of soil 
gin of fertilisation of soil. The effect of bacterised peat on plants was shewn 
m photographs taken and converted into lantern slides. 
