214 
cand d@ are constants, then the relation connecting these quan- 
tities with 2 is 2 =c + d log w (360 — w). If the distance of 
the disc from the illuminant is now varied, so that I varies, the 
equation connecting all these quantities with 7 (the number of 
rotations of the disc per second when flicker just vanishes) is 
n=k + k' logI. log w(360 - w), where £ and %’ are constants 
(though it must be remembered that 2’ has a different value 
for very feeble illuminations). All these results are clearly 
exhibited in the paper by numerous interesting curves. It is 
also shown that the different curves obtained by placing the disc 
in the different colours of the same spectru'm, and varying the 
angle of the white sector by steps of 10° from 0° to 180° in each 
colour, can all be obtained by viewing the disc illuminated by 
white light and simply varying the intensity of the illumination, 
which proves that 7 is unaffected by the wave frequency of the 
different colours and is solely influenced by their intensity. 
Finally a curve, showing the relative intensity of the light of 
different parts of the same spectrum, deduced from the results 
of the present paper, is given, and proves to be actually co- 
incident, within the errors of experiment. (except for the very 
faint illuminations at the two ends of the visible spectrum) with 
the curve expressing the same thing given by Vierordt, but 
obtained by him, as by Abney and others, in an altogether 
different way. 
“The Spectra of Potassium, Rubidium and Cesium, and 
their Mutual Relations.” By Hugh Ramage. B.A., St. John’s 
College, Cambridge. Communicated by Prof. G. D. Liveing, 
F.R.S. 
Tables of the oxyhydrogen flame spectra of the above three 
metals are given, which contain a number of lines not hitherto 
recorded. The lines which form the second subordinate series 
of czsium and several members of the corresponding series of 
rubidium are new; so also are some of the lines of the first 
subordinate and the principal series of both metals. The flame 
spectra were photographed with a spectrometer fitted with a 
Rowland plane grating ; spark spectra of iron, titanium, &c., 
were superimposed on the flame spectra to furnish fiducial lines. 
Some of the lines in the red region of the spectrum were 
measured by eye observations. 
Diagrams of the subordinate series in the spectra were drawn 
to scales of oscillation frequencies for abscissze and (1) atomic 
masses, (2) squares of atomic masses for ordinates. The con- 
clusions deduced in the author’s previous paper (Hoy. Soc. Proc., 
vol. Ixx. p. I, 1902) from less complete data were amply con- 
firmed. There is undoubtedly a very close connection between 
these series and the atomic masses, and the lines which connect 
the corresponding members of homologous doublets in diagram 
(2) do intersect on the ordinate of zeroatomic mass. The points 
which bisect the limits towards which the subordinate series 
converge in each spectrum lie on straight lines in diagram (1). 
The constants in Rydberg’s general formula were then expressed 
in terms of the atomic masses; the oscillation frequencies of 
the lines, calculated from the modified formula, are given in the 
paper, together with the observed numbers. The convergence 
points of the series were calculated by different methods and 
the results are given. It would appear from these that the 
two subordinate series do not converge towards the same limits. 
All the strong lines and nearly all the weak lines which have 
been observed in the flame and arc spectra of these three metals 
are included in the three harmonic series. The differences 
between the corresponding series in the spectra appear to 
depend on the atomic masses alone. Reasons are also given 
for thinking that the principal and the second subordinate 
series are more closely related to each other than to the first 
subordinate series. 
Chemical Society, June 5.—Dr. Thorpe, C.B., F.R.S., in 
the chair.—The action of ungerminated barley diastase on starch, 
parti., by Dr. J. L. Baker. The hydrolytic products of this action 
are a new amylodextrin and maltose. The former is slowly con- 
verted by the further action of the enzyme into maltose and a 
small proportion of dextrose. The lecomposition of chlorates, 
part v., potassium chlorates in presence of oxides of manganese 
and the theory of perchlorate formation, by Mr. W. H. Sodeau. 
It is shown that, since the amount of chlorine produced by 
heating potassium chlorate in presence of manganese dioxide is 
not increased by reduction of pressure, no secondary reaction can 
occur, and therefore McLeod’s theory of permanganate forma- 
tion is untenable.—Studies in the tetrahydronaphthalene series, 
i, the diazo-amino-compounds of av-tetrahydro-8-naphthalene, 
NO. 1704, VOL. 66] 
NATURE 
[JuNE 26, 1902 
by Mr. C. Smith.—Experiments on phosphorus tetroxide, by 
Mr. C. A, West. When phosphorous oxide, P,O,, is heated 
at 300°, it decomposes into phosphorus tetroxide and free 
phosphorus. The former is an extremely stable substance, 
volatilising only with difficulty at 1400°. Its composition is re- 
presented by the formula PgO,,. The decomposition of compounds 
of selenium and tellurium by moulds and its influence on the 
biological test for arsenic, by Dr. Rosenheim. Certain 
moulds, such as <Aspergtllus, Mucor and Penicillium, de- 
compose tellurium and selenium compounds with the pro- 
duction of a feecal odour which masks the garlic odour 
given off by these moulds when grown in arsenical solutions, — 
Constituents of gambier and acacia catechus, by Messrs. A. G. 
Perkin and E. Yoshitake. The authors have isolated from 
these sources three closely related substances, distinguished as 
catechins a, 6 and c.—The decomposition of oxalacetic hydr- 
azone in aqueous and acid solutions, and a new method of 
determining the concentration of hydrogen ions in solution, by 
Messrs. H. O. Jones and O. W. Richardson. When the 
hydrazone is heated in aqueous solution it decomposes into 
pyruvic hydrazone and pyrazolone carboxylic acid, the produc- 
tion rate of the former being proportional to the concentration 
of the original hydrazone, and of the latter to the concentration 
both of the hydrazone and the hydrogen ions.—The dissociation 
constants of oxalacetic acid and its hydrazone, by Messrs. H. O. 
Jones and O. W. Richardson.—Derivatives of butyrylpyruvic 
acid, by Dr. A. Lapworth and Mr. A. C. O. Hann.—Sulpho- 
campholene carboxylic acid, by Mr. A. W. Harvey and Dr, 
Lapworth.—Some properties of camphorquinonephenylhydr- 
azone, by Dr. A. Lapworth and Mr. A. C. O. Hann. The 
authors have been unable to obtain the “keto” form of this 
substance in a pure state, but have obtained evidence of its 
existence and have studied the rate at which equilibrium 
between the ‘‘keto” and ‘‘enol” forms is attained under 
various conditions.—Optically active esters of 8-ketonic and 
B-aldehydic acids, part i., menthyl hydroxymethylenephenyl- 
acetate, by Dr. Lapworth and Mr. A. C. O. Hann. The 
authors propose to investigate these esters in the hope of 
obtaining an insight into the peculiar tautomeric relations of 
the acids from which they are derived.—Part ii., menthyl 
acetoacetate, by Dr. Lapworth and Mr. A. C. O. Hann.—The 
mechanism of simple desmotropic change, by Dr. Lapworth 
and Mr. A. C. O. Hann. An extension of Briihl’s views on 
the mechanism of tautomeric change.—Trimethylbrazilone, by 
Dr. W. H. Perkin, jun. An investigation is being made into 
the constitution of this substance, which is obtained by the 
oxidation of brazilin. 
Entomological 
Fowler, president, 
Society, 
June 4.—The Rev. Canon 
in the chair.—Mr. 
H. W. Shepheard- 
Walwyn exhibited a male specimen of LampzdeS baeticus taken . 
recently emerged at Winchester in September, 1899, and two 
varieties of Lycaena icarus.—Mr. C. P. Pickett exhibited one 
asymmetrical male and two females of Dz/inza fliae, and a 
series of the same insect showing great variation in colouring 
and markings, bred during May, 1902.—Mr. F. Merrifield ex- 
hibited photographs showing the protective resemblances of the 
larva and pupa of Hygrochroa syringaria.—Prof. E. B. Poulton 
exhibited a lantern slide showing the perfect protective re- 
semblance of AHybernia leucophaearta to the oak trunk upon 
which it rested.—Mr. A. Bacot exhibited hybrid larvz resulting 
from a pairing between a male Malacosoma neustria and a 
female 47. castrensts, also larve of AZ neustria and reputed 
larve of MZ. franconica for comparison.—Mr. TH. C. Elwes 
read a paper on the butterflies of Chile, illustrated with many 
specimens taken during an expedition last winter to that country. 
The poverty of the Chilian rhopalocerous fauna is notable. Of 
the insects represented there was probably only one really 
Chilian Colias, the most numerous family being the Satyridze, 
of which some twenty-five species were taken. The Nymphalidee 
are few in number, while three native Theclids and three 
Lycenids represent their respective groups. Mr. Elwes drew 
especial attention to one unique species, Argurophorus 
argenteus, which flies at 3000 to 7000 feet, the upper-side of 
all the wings in male and female being unicolorous and brilliant 
metallic silver, the under-side resembling somewhat that of the 
Holarctic family CEneis. A similarly beautiful golden sheen 
was observable on Cyclopides puelmae, a species of Hesperid, 
but on the ground of protective coloration there seemed nothing 
in the surroundings of either insect to account for the peculiarity. 
Between alpine and lowland species there was no distinction, 
