Dec. 8, 1881] 
not exhibit the inverse function ; (4) there is some evidence that 
the precipitabilities of the commixed and separate sulphates are 
mathematically related in a simple manner ; (5) within moderate 
limits precipitation is not traceably affected by temperature. 
‘*Researches on Chemical Equivalence.” By Edmund J. 
Mills, D.Sc., F.R.S., and Bertram Hunt. Part V.: Nickelous 
and Cadmic Sulphates. 
This series of experiments had for its object the comparison 
(as in Part IV.) of nickelous sulphate with a sulphate belonging 
to another group. The precipitability equations for the com- 
mixed salts are given; and it is shown that, according to these, 
nickelous and cadmic sulphates do not admit of comparison as 
equally precipitable substances. The authors say, in conclusion, 
‘*Our present inference with regard to the precipitability of 
nickelous-cadmic salt will lead (if confirmed by the action of 
reagents other than sodic carbonate) to the following important 
criterion :—77wo elements belong to the same group when, in saline 
solutions of identical genus, they may be equally precipitable. 
“‘Note on the reversal of the Spectrum of Cyanogen,” by 
Professors Liveing and Dewar. 
The authors have frequently noticed dark shaded bands which 
appeared to be the reversals of bands of oxides or chlorides of 
sundry metals, but only recently have they obtained photographs 
showing the reversal of the violet and ultra-violet flutings of 
cyanogen. The most complete reversal of these flutings were 
obtained by the use of a Siemens’ machine in a crucible of 
magnesia fed with cyanide of titanium. No other cyanide has 
been found to produce this effect, but borate of ammonia has 
produced the reversal of the strongest group nearL. In one 
case the reversal was produced by the bright background given 
by the expanded lines of magnesium when that metal was intro- 
duced. Probably the great stability of titanic cyanide and boron 
nitride has an influence on the result. The difficulty in repro- 
ducing the reversal at will is in securing an absorbing stratum of 
sufficiently high temperature, and at the same time a sufficiently 
bright background, 
Geological Society, November 16.—R. Etheridge, F.R.S., 
president, in the chair.—Dr. T. Sterry Hunt, who was present 
asa guest, gave some account of the pre-Cambrian or Eozoic 
rocks of Europe as compared with those of North America, 
He had on several occasions studied them, both on the Continent 
and in the British Isles, especially with Dr. Hicks in Wales in 
1878. In North America the recognised base is a highly granit- 
oid gneiss, without observed limestones, which he has called the 
Ottawa gneiss, overlain, probably unconformably, by the Gren- 
ville series of Logan, consisting chiefly of granitoid gneisses, 
with crystalline limestones and quartzites. These two divisions 
make up the Laurentian of Canada, and correspond respectively 
to the Lewisian and the Dimetian of Hicks. Resting in dis- 
cordance on the Laurentian, we find areas of the Norian or 
Labrador series (Upper Laurentian of Logan), chiefly made up 
of anortholite rocks, granitoid or gneissoid in texture, with some 
true gneisses. The Huronian is seen to rest unconformably on 
the Laurentian, fragments of which abound in the Huronian 
conglomerates. To, the lower portion of the Huronian the 
speaker had formerly referred a great series of petrosilex or 
halleflinta rocks, described as inchoate gneisses, passing into 
petrosilex-porphyries, occasionally interstratified with quartzites, 
This series, in many places wanting both in Europe and America, 
he is now satisfied forms an underlying unconformable group— 
the Arvonian of Hicks. Above the Huronian is the great Mont- 
alban series, consisting of grey tender gneisses and quartzose- 
schists, both abounding in muscovite, occasionally with horn- 
blendic rocks. The Pebidian of Hicks includes both the 
Huronian and the Montalban, to which latter belong, according 
to the speaker, certain gneisses and mica-schists both in Scotland 
and in Ireland, as he had many years since pointed out. In 
some parts of North America he found the Montalban resting 
unconformably on Laurentian. Above the Montalban comes 
the Taconian (Lower Taconic of Emmons), a series of quartz- 
ites and soft micaceous schists, with dolomites and marbles, All 
these various series are older than the Lower Cambrian (Mene- 
vian) strata of North America; and it may be added that the 
Keweenian or great copper-bearing series of Lake Superior there 
occupies a position between the Montalban and the Cambrian. 
In the Alps the speaker recognises the Laurentian, Huronian, 
and Montalban, all of which he has lately seen in the Biellese, 
at the foot of Mont Viso, in Piedmont. The Huronian is the 
great pietre verdi group of the Italians, and much of what has 
been called altered Trias in thig region is, in his opinion, pro- 
NATURE 
143 
bably Taconian, The Montalban forms the southern slope of 
Mont St. Gothard, and is the muscovite gneiss and mica-schist 
of the Saxon Erzgebirge. Here Dr. Credner and his assistants 
of the Geological Survey have described abundant conglomer- 
ates holding pebbles of Laurentian rocks imbedded in the Upper 
or Montalban gneiss, The pre-Cambrian age of this has been 
shown by Credner, who has proved by careful survey that the 
so-called younger or Palaeozoic gneisses of Naumann are really 
but a continuous part of the older series. Late surveys also 
show that the crystalline rocks of the Taunus are really Eozoic, 
and not, as formerly maintained, Devonian in age. The speaker 
insisted upon the fact that where newer strata are! in uncon- 
conformable contact with older ones, the effect of lateral move- 
ments of compression, involving the two series, is generally to 
cause the newer and more yielding strata to dip towards and 
even beneath the edges of the older rock, a result due to folds, 
often with inversion, sometimes passing into faults. This phe- 
nomenon throws much light on the supposed recency of many 
crystalline schists. —The following communications were read :— 
Additional evidence on the land plants from the Pen-y-glog 
slate-quarry, near Corwen, by Henry Hicks, M.D., F.G.S.— 
Notes on Pro/ofaxites and Pachytheca from the Denbighshire grits 
of Corwen, North Wales, by Principal Dawson, LL.D., F.R.S., 
F.G.S. 
Zoological Society, November 29.—Dr. A. Giinther, 
F.R.S., vice-president, in the chair.—A letter was read from 
Dr. A. Frenzel announcing his success in breeding parrots of 
the genus Zc/ectus in his aviary at Freiberg, in Saxony.—A 
communication was read from Dr. A. B. Meyer, C.M.Z.S, con- 
taining the description of a new species of #c/ectus received from 
Timorlaut Island, which he proposed to name Zelectus riedelt.— 
Mr. R. Bowdler Sharpe read a note on the genera Schenicola 
and Cat¢riscus, and pointed out that these genera were identical, 
but that the South-African S. aficalis was specifically distinct 
from the Indian S, platjura.—Mr. G. A. Boulenger gave the 
description of a new species of Avolzs from Yucatan, proposed to 
be called Anolis beckeri.—Mr. W. A. Forbes gave an account of 
the observations he had made on the temperature of the Indian 
Python (Python molurus) during her incubation in the Gardens 
of the Society in June and July last. The result arrived at was 
that in the present case there was a difference on the whole 
average of about 1°°4 Fahr. in favour of the female as compared 
with the non-incubating male when the temperature was taken 
on the surface, and of more than double that amount when the 
temperature was taken between the folds of the body.—Dr, 
Gwyn Jeffreys, F.R.S., F.Z.S., read the fourth of his series of 
papers on the Mollusca procured during the expeditions in 
H.M SS. Lightning and Porcupine, 1869 and 1870, This part 
concluded the Conchifera or Bivalves. Eighteen additional 
species, chiefly belonging to the genus Meera, which is peculiar 
to deep water, were described. The geographical, hydro- 
graphical, and geological distribution, as well as the synonymy 
of all the species named in the paper, were treated of. —A com- 
munication was read from Dr. G. Hartlaub, describing the birds 
collected in Socotra and Southern Arabia by Dr. E, Riebeck. 
Amongst the Socotran birds was an example of a new species of 
finch of the genus RAynchostyuthus, which he proposed to call, 
after its discoverer, R. riebecki. 
Royal Microscopical Society, November 9.—J. W. 
Stephenson, vice-president, in the chair.—The Rey. J. J. 
Halley, vice-president of the Microscopical Society of Victoria 
(one of the affiliated societies), attended the meeting, and gave 
an account of the progress of biology and microscopy in that 
colony.—Mr. Stephenson exhibited a slide of Surivella gemma, 
mounted in phosphorus, illustrating in a remarkable manner the 
advantage of mounting in media of high refractive index. Mr. 
Crisp, Mr. Crossley, and Mr, Watson exhibited various forms of 
microscopes and apparatus, and Mr. Mayall an Abbe apertometer 
of dense glass for measuring apertures up to 1°50 N.A., anda 
plate ruled by Fasoldt of New York, who claims to be able to 
rule lines up to 1,000,000 in the inch.—The deaths of M. 
Nachet, sen., of Paris, and Mr. C. A. Spencer of Geneva, 
N.Y., were announced.—Two papers were read by Dr. B. 
Wills Richardson on multiple staining of animal and vegetable 
tissues, and by Dr. L. G. Mills on diatoms from Peruvian 
guano; and Mr. T. Charters White exhibited and explained 
Goodwin’s growing slide.—Eight new Fellows were elected. 
Anthropological! Institute, November 22.—Mr. Hyde 
Clarke, vice-president, in the chair,—The election of C. 
