May 8, 1902] 
NATURE 
45 
THERE will be an exhibition of scientific apparatus at the | 
conference of science teachers to be heldat Festiniog on May 15 
(see p. 599, April 24). Good apparatus is urgently required in 
many Welsh schools, and manufacturers ought to hasten to avail 
themselves of the opportunity which the conference affords of 
exhibiting instruments and materials essential to practical in- 
struction in science. Mr. J. Griffith, County School, Fes- 
tiniog, has entire charge of the exhibition arrangements, and 
| diminution. 
would provide rooms and allocate space for the display of | 
scientific apparatus. 
Tue Technical 
Council will shortly award five senior county scholarships. The 
scholarships are open to young men and young women who are 
resident within the administrative county of London whose parents 
are in receipt of an income not exceeding 400/. a year.. They 
are tenable for three years at British or foreign Universities and 
technical colleges of University rank, and are of the value of 
go/. a year. Candidates should as a rule be not more than 
twenty-two years of age, preference being given to those who 
are under nineteen years of age. In addition to the scholar- 
ships, the Board offers for competition a limited number of free 
places at the principal London colleges. Application forms can 
be obtained from the secretary of the Technical Education 
Board, and must be returned not later than Monday nest, 
May 12. 
A MEETING of the Association of Technical Institutions will 
be held between the second reading of the Government Edu- 
cation Bill and the Committee stage. At this meeting the 
council will recommend the Association to adopt the following 
resolutions in regard to the Bill:—(1) That this Association 
cordially approves the general principles upon which the 
Government Education Bill is based, and strongly urges His 
Majesty’s Government to pass the Bill in the present session of 
Parliament. (2) That this Association is strongly of opinion 
that the new local authorities should be responsible for all grades 
of education in their districts, and that proper educational co- 
principle were not adopted ; it therefore urges the Government | 
to amend the Bill by deleting the clauses making it optional for 
the County and Borough Councils to undertake the supervision 
of elementary education. 
note that the Bill makes optional the application to the purposes 
of higher education of the residue under the Local Taxation 
(Customs and Excise) Act, 1890, and it requests the Govern- 
ment to make such application compulsory. (4) That this 
Association regrets the exclusion of London from the Bill and 
trusts that the metropolis may receive attention early next year, 
Education Board of the London County | 
(3) That this Association regrets to | 
tannic acid. Experiments on the circulation in the lung and 
mesentery of the frog reveal a close similarity between the action 
of the Spurge-extract and of tannic acid. In the case of trout 
the similarity extends to the non-recovery of the fish in fresh 
water, after they have come under the influence of either 
Spurge-extract or tannicacid. The power of the Spurge-extract 
to produce fatal effects persists for several days without 
Twenty per cent. of the fresh extract is fatal 
within five minutes, whilst o’or per cent. takes 4 to 6 hours, 
and seems to be the smallest percentage which has fatal results. 
In the case of fishes, death is considered to ensue from the 
inflammation of the gills and consequent stasis of the circulation, 
set up by the action of the tannic-acid component of the Spurge- 
extract. The fresh extract is calculated roughly to contain 
about I per cent. of tannic acid, but on this estimation the 
| Spurge-extract is fatal within a shorter period than the corre- 
sponding quantity of tannic acid. Hence, the percentage of 
tannic acid has been under-estimated, or some other substance 
or substances in the extract also aid in producing fatal effects. 
March 20.—‘‘ Persulphunic Acids.” By Prof. Henry E. 
Armstrong, V.P.R.S., and T. Martin Lowry, D.Sc. 
The ‘‘ remarkable disappearance of oxygen” which Faraday, 
in 1834, observed to take place on electrolysing strong solutions 
of sulphuric acid was shown by Berthelot, in 1878, to be due 
mainly to peroxidation of the sulphuric acid. An anhydride, 
| S,0;, was isolated, and he therefore concluded that the cor- 
responding perd/sulphuric acid, H,S,O3, was formed when 
sulphuric acid was peroxidised either by anode oxidation or 
by interaction with hydrogen peroxide. The perdzsulphates 
were isolated by Marshall, in 1891, by electrolysing solutions of 
acid sulphates, and have found a technical application in 
photography. This simple explanation of the peroxidation of 
sulphuric acid remained unchallenged until Caro found, in 1898, 
that when the perdzsulphates are dissolved in sulphuric acid and 
the solution is again neutralised, a product is obtained which 
possesses the property of oxidising aniline to nitrosobenzene. 
é 1 lal co- | None of the salts of Caro’s modified persulphuric acid have 
ordination would be seriously and unnecessarily hindered if this | 
and, while recognising that the case of London requires special | 
treatment, is of opinion that it would be unwise to depart from 
the general principles of the present Bill in the case of London. 
SOCIETIES AND ACADEMIES. 
LONDON. 
Royal Society, December 12, 1901.—‘ On the Action of | 
the Spurge (Zuphorbia hiberna, L.) on Salmonoid Fishes.” By 
H. M. Kyle, M.A., D.Sc., St. Andrews University. Communi- 
cased by Prof. McIntosh, F.R.S. 
It has been known for some years that the Irish peasantry 
employed a simple method of procuring salmon and trout 
through the agency of the Spurge (Z. Azberna, L). The plant 
cut into small pieces and pounded with stones, or simply 
trampled upon at some convenient spot ona river, forms an 
emulsion in the water which, being swept downward into the 
pools, carries death to all fishes in its course. The fatality thus 
produced seems to have been enormous—8o to 100 salmon are 
reported to have been killed at one time, and again in the | 
Bandon rivers 500 to 1000 fish of various descriptions are said 
to have been poisoned during one season. In the light of the 
experiments to be recorded presently, these statements do not | 
seem exaggerated, for the Spurge-extract, even in small quan- 
tities, is almost as fatal to fishes as corrosive sublimate. 
The fatal effect of the Spurge on fishes has been known in | 
other countries besides Ireland, but to what ingredient or 
ingredients of the plant these effects are due seems never to 
have been investigated. The experiments described in the 
present paper throw considerable light upon the action of the 
Spurge, and open out to view some interesting problems. 
yet been isolated, and only indirect methods are therefore 
available for determining its constitution. 
Von Baeyer and Villiger have determined the ratio of sulphur 
to active oxygen in a solution containing the barium salt of Caro’s 
acid, and found the ratioto be SO,: O=1: 1, the ratio for Mar- 
shall’s salts being SO,: O=2:1. Theytherefore assigned to 
Caro’s acid the formula H,SO, of a permonosulphuric acid. If 
this acid be dibasic its salts must remain neutral when reduced, 
thus CaSO;,=CaSO,+0O, whereas any higher member of the 
series would liberate acid, thus CaS,O3+H,O=CaSO,4+ 
H,SO,+0O. Caro’s salts are extremely unstable in presence of 
caustic alkalis, but neutral solutions can be prepared by 
neutralising with carbonates ; when such solutions are heated 
they lose their active oxygen and liberate acid in the ratio 
H,SO,:O,. This result can only be reconciled with the 
| formula of von Baeyer and Villiger by assuming per/zono- 
‘Chemical analysis of the Spurge-extract shows that it contains 
NO. 1697, VOL. 66] 
sulphuric acid to be monobasic, NaHSO;=NaHSO,+0; a 
more probable view is that Caro’s acid is the anhydro-acid, 
750,-0.0H 
<< , and that its salts are comparable with the 
SO,.0.0H 
pyrosulphates and the dzchromates, CaS,O, + H,O=CaSO,+ 
H,SO, + Oo. 
In concentrated solutions containing less than 50 per cent. of 
water, the peroxidation of sulphuric acid proceeds differently, 
the chief product being probably a per/e¢vasulphuric acid, 
| H,S,0O,, (Lowry and West, Chem. Soc. Zyans., 1900, 950). 
This acid, the fourth member of the series H,O,.nSO3, bears 
to pyrosulphuric acid the same relationship as that which per- 
disulphuric acid bears to sulphuric acid, 2H,S,0,—-H,= 
H,$,04, 2H,SO,— H,=H,S,O,. On dilution and neutralisa- 
tion it is hydrolysed to a salt of Caro’s acid. 
At the present time it is therefore necessary to postulate the 
existence of at least three persulphuric acids, in which the ratio 
SO, : Ois 1:1, 1:2and 1: 4 respectively. In spite of the stability 
of the perdisulphates, the least stable of these is perdzsulphuric 
acid, for when liberated from its salts it rapidly passes in dilute 
solution to a per/ovosulphuric acid (Caro’s acid), whilst in 
presence of concentrated sulphuric acid it is converted mainly 
into per/e/rvasulphuric acid. 
“On a Throw-testing Machine for Reversals of Mean Stress.” 
By Osborne Reynolds, F.R.S., and J. H. Smith, M.Sc. 
This research was undertaken at the suggestion of Prof. 
