Scientific Intelligence, <§ c. 
113 
dry months, and will also be protected by its outer or flood pates from the violent 
influx of river water, which would otherwise obtain rvhon the river is at its highest, 
or 11 feet above the wafers of the lake. A constant passage will be available for 
purposes of navigation of several hours during each tide throughout the. year, and 
suflieient influx of water from the river will be allowed to prevent the new canal 
from stagnating and presenting an appearance so disgusting and insalubrious as the 
present eastern Canal. The Circular canal is not immediately connected with any 
new system of town drainage in contemplation ; but the subject appears not to have 
been left unconsidered, and much facility in such respects may he confidently expect- 
ed from the position and proposed management of its water level. 
About 3,000 labourers are now employed daily on the excavations, and the depth 
already reached, is in many places lb feet. The final completion of the work may 
be looked for in 1831. - 
2 . Baron Cuvier's New Work on Fishes. 
A very full prospectus has reached us of a new work on fishes, preparing for pub- 
lication by the above celebrated naturalist. To judge from the details given of the 
assistance and contributions that have been offered to the work — as well as of the 
general plan which it is proposed to follow in the execution — we would say that it is 
likely to increase, if possible, the high reputation due to the name of Cuvier in 
every civilized country of the globe. The Royal Cabinet which furnishes the ground- 
work of his labours is said to consist of 5,000 species and 15,000 specimens. A great 
part of these bare been arranged so as to give a clear idea of the comparative ana- 
tomy of this class of animals, and being ticketed gild deposited in the Museum of Com- 
parative Anatomy with references to the present work, they will form an easy means 
of verifying any details, and of ascertaining clearly the identity' of any species. The 
names of those who have given their assistance or promised it, would form a list of 
the most distingtu'shed men in Europe, inthis branch of natural history. In particular, 
however, M. Valenciennes, assistant naturalist in the Royal Museum, is stated to be 
his principal coadjutor, and the work is announced as their joint production. A very- 
full history of Ichthyology is promised, comprising a critical analysis of all the 
works hitherto published on the subject of fishes. 
The synonymes, which are not unfrcqucntly the most puzzling branch of a 
science, have lmd particular attention paid to them ; and from the large means of 
verifying descriptions placed at his disposal, it is probable that every justice will be 
done to this division of the work. 
MM. Werner and Laurdlnrd have undertaken to furnish drawings for the plates. 
tu ' plate at least will be given for each groupe of species, and when called for by 
any peculiarity in the species, two or more. 
For tlie terms of subscription and other particulars, we refer to our cover. 
3. Woollaslon's Thermometrical Barometer. 
The thermometrical barometer, if its construction were so simplified that it might 
lie afforded at one or two guineas, might, I think, he brought into general use. It is 
a very useful instrument, and might be employed occasionally as a substitute for the 
barometer, but always witli advantage as an accompaniment and auxiliary ; and the 
comparison of the results of the two instruments made on very elevated mountains, 
such as the Himmalaya, would be very desirable and interesting. The principle of 
the thermometrical barometer is good, and it Is independent of the specific gravity 
of the mercury, which is an advantage ; but on the other hand the boiling point would 
he shown a little differently according to the quality of the water boiled ; rain water, 
spring, river, and snow water* would, I suppose, give different points in an instru- 
ment of so much sensibility. The instruments which have been sent out would he 
useless in a survey: it requires a steady hand to put them into the curious tubes of 
copper and tin, of which the cases are composed, without breaking, and a fall would 
be fatal to them ; — indeed they are most fragile instruments, far more so than the 
* These two, with distilled water, woold most probably have the same boiling point, 
thousli the others would be likely to differ. There appear, however, to be some un- 
certainties, in the determination of the boiling point, independent of the nature of 
the water, the cause of which is not very dearly ascertained. It has been found, 
tor instance, that water boils in platina vessels at 1° lower temperature than in 
glass; and that vessels of different materials have different boiling points. Also 
that a few pinches of metallic filings, or bits of metallic wire being thrown into a 
liquid, occasion it to boil at a lower temperature than it otherwise would. — Eo. 
