286 
A RECENT AND VALUABLE DISCOVERY. 
6. Tennipes Senegal. 7. Indica Bengal. 8, Assi- 
niilis. 9. Abdominalis. 10. Fumipennis, 
Senegal. 11. Punctiger West Africa. 12. 
Signata Sierra Leone. 13. Fasciata. 14. 
Concolor West Africa. 15. IMacrophthalma 
Siena Leone. 16. Thoracica West Africa. 
17. Obscura Sierra Leone. 1. Confasa 
Congo, Sumatra. 19. Dalmanni Java, 
20. Sykesii East Indies. 21. Brevicornis 
Pennsylvania. 
This paper is illustrated by engravings of 
twenty figures. 
CONSTANT VOLTAIC BATTERY. 
Professor Daniel, of King’s College, exhi- 
bited his battery on the 6th inst., at the Royal 
Institution. He was led to construct this 
very beautiful apparatus, by following up the 
investigations of Davy and Fai’aday. He 
found that the protecting power of tin on cop- 
per sheathing, was due to a chemical action. 
Thus he placed a plate of silver in a solution 
of sulphate of copper ; and on touching it with 
a fine-pointed rod of zinc, he found the cop- 
per deposited on it in a circular form, and in 
a regular manner ; and, if the contact was 
kept up, the whole plate was supplied with a 
copper coating. The elfect of protecting me- 
tals appeared, at first, an objection to the 
chemical theoi*y of electricity ; but this experi- 
ment demonstrates its truth. To determine 
and measure the definite chemical action of 
electricity, Mr. Daniel has constructed a 
dissected battery. It consists of ten cylindrical 
glass vessels, which contain the fluid electro- 
lytes ; the two plates of metal are immersed 
in these fluids, each plate communicating 
below by means of a separate wire, which is 
made to perforate a glass stopper closing the 
bottom of the cell, with a small quantity 
of mercury contained in a separate cup below 
the stopper. The plates consisted of amal- 
gamated zinc and platinum ; the electrolyte 
consisted of 100 water, and 2’25 sulph. acid. 
He found that by increasing the size of the 
platinum plates, the action was promoted, 
and that the zinc might be reduced to the size 
of a wire, with the same effect as when a 
plate was used. Iron answers in place of the 
platinum, but not instead of zinc. The dilute 
acid described, has little action on the amal- 
gamated zinc, because the'latter becomes spee- 
dily covered with bubbles of hydrogen, which 
mar its action. — When nitric acid is added, 
the plate is soon dissolved, without extrica- 
ting any gas, in consequence of the elements 
of the nitric acid combining with the nascent 
hydrogen. N ascent hydrogen also deoxidates 
copper. To remove the hydrogen, he con- 
structed the constant battery ; which consists 
of a copper cylindrical vessel, containing in 
its axis, a membranous tube formed of the 
(Esophagus of an ox, in which is suspended a 
rod of zinc. Diluted acid is poured into the 
membranous tube, by means of a funnel ; and 
passes off by a syphon, communicating with 
the bottom. The space between the animal 
lube and the sides of the copper cylinder, is 
filled with a solution of sulphate of copper^ 
and pieces of this salt, to keep the solution 
saturated. By this arrangement, the oxide 
deposited is removed as it is formed, by the 
syphon tube ; and the hydrogen evolved from 
the surface of the copper, is absorbed. For, 
on completing the circuit, the electric current 
passes freely through the blue vitriol solution, 
and no hydrogen appears on the conductor ; 
but the latter is covered wdth a coating of 
pure copper. The advantages of this battery 
are obvious ; it may be kept for hours in ac- 
tion, with the same power, and is economi- 
cal. — Records of Science, June, 1836. 
THE INDIA REVIEW. 
Calcutta: October IS, 1836. 
INDIA ASSOCIATION FOR THE AD- 
VANCEMENT OF SCIENCE. 
When we witness the great number of 
well educated youths so well prepared for en- 
tering upon collegiate systems of study as 
at the High School, the Parental Academy, 
and the other seminaries at the Metropolis, 
it becomes a matter of regret that there is no 
institution in this city, to which the senior 
students can have access for the attainment 
of the higher branches of professional and 
scientific education. To supply the desider- 
atum we understand it is in contemplation 
to build a theatre or lecture room, on 
extensive grounds, and to establish an Indian 
association for the advancement of Science 
and mechanical arts. The chief aim of this 
%stitution is to qualify young men for the 
practice of the learned professions, as 
well as to teach practically the me- 
chanical arts. The model is to be that of the 
French Ecole Poly technique, which may, 
without doubt, be as successfully carried 
into execution in India as it was in France. 
The Ecole Polytechnique took its rise under 
the auspices of Mo nge, Haiiy, Hassenft-aetz, 
La Place, La Grange, Fourcroy, Chaptal, . 
Poney, and others. Other schools of science ' j 
were also establish ed. They had 1300 pupils , j 
of whom different professors took charge in 
their respective sciences. The system was vast, 
and such was the progress and acquirement 
