172 
that in addition to various other eminent men, the following, as 
representatives of literature, science, and art, be invited to be- 
come vice-presidents of the guild :—Prof. Huxley, Sir Francis 
Grant, Mr. Alfred Tennyson, Dr. W. B. Carpenter, Prof. Tyn- 
dall, Sir Antonio Brady, Lord Lyttelton, Mr. Thomas Hughes, 
M.P., Mr. J. A. Froude, and Sir Sterndale Bennett. It was 
further resolved that the annual subscription for ordinary mem- 
bers be one shilling or upwards, and for associate members one 
guinea or upwards ; that application should be made for dona- 
tions to meet the preliminary expenses, and to furnish an income 
until the society is self-supporting ; and that a prospectus of the 
objects and plans of the society should be issued as soon as 
possible. 
CoMMODORE SELFRIDGE has returned to the Navy Depart- 
ment at Washington, bringing with him the materials for pre- 
senting a detailed report of his exploration upon the Isthmus of 
Darien during the past winter in reference to the construction of 
an inter-oceanic ship-canal. The result of his inquiries has been 
much more favourable than was anticipated, and it is now esti- 
mated that only twenty-eight miles of canal need be constructed, 
the remainder of the distance consisting of the perfectly navi- 
gable waters of the Atrato, Doguado, and Napipi rivers. A 
tunnel will still be necessary, as estimated on a previous ex- 
ploration, but this will only require to be three miles in length, 
instead of five, and it is estimated that the entire distance can be 
completed at a cost of less than 70,000,000 dols. Twenty-two 
miles of the canal are over an almost level plain, and only nine 
locks in all will be needed. 
WE have just received the first number of the Bulletin, or 
Proceedings of the Society of Natural History of Buffalo, New 
York. Four similar numbers are to be issued each year, with a 
few plates. The number before us is solely occupied by the 
work of Mr. Aug. R. Grote, who contributes four papers 
describing new North American Moths, and giving catalogues 
of the Sphingidae and Zygaemidae of North America, followed 
by conclusions drawn from a study of the genera Hypena, and 
Herminia. 
SINCE the diffraction spectrum differs from a prismatic spec- 
trum of the same length in having the less refrangible rays more 
widely dispersed, it some time ago suggested itself to Prof. C. 
A. Young that a so-called gitter-plaite or ‘‘ grating ” of fine lines 
might advantageously replace the prisms in spectroscopes de- 
signed for the observation of the solar prominences through the 
C line. Having recently obtained one of the beautiful gratings 
ruled upon speculum metal, having a ruled surface of something 
more than a square inch, the lines being spaced at intervals of 
ges Of an inch, he combined this with the collimator and tele- 
scope of a common chemical spectroscope, thus getting an instru- 
ment furnishing a spectrum of the first order, in which the D 
lines are about twice as widely separated as by the flint glass 
prism of 60° belonging with the original instrument. In 
the neighbourhood of C the dispersion is nearly the 
same as would be given by four prisms, The spectra 
of the higher orders are generally not so well seen on 
account of their overlapping «each other, but fortunately 
with one particular adjustment of the angle between the collima- 
tor and telescope, the C line in the spectrum of the third order 
can be made to fall in the vacant space between the spectra of 
the second and fourth orders. On applying the new instrument 
to the equatorial, Prof. Young found that in the first order 
spectrum he could easily ‘see the bright . chromosphere lines 
C, Dj, and F ; he could also, though with great difficulty, make 
out Hy, (2796K). On opening the slit the outline of the chro- 
mosphere and the forms of the prominences were well seen, 
both in the spectra of the first and third order. The grating is 
much lighter and easier to manage than a train of prisms, and 
NATURE 
[Kune 26, 1873 
if similar ruled plates can be furnished by the opticians at reason- 
able prices and of satisfactory quality, it would seem that for 
observations upon the chromosphere and prominences they might 
well to some extent supersede prisms. 
THE Eleventh Annual Report of the Free Libraries Com- 
mittee of Birmingham is very carefully drawn up. It contains 
some valuable analytical tables showing the average numbers 
of those who daily take advantage of the library, the ages of 
the readers, their occupations, along with the number of 
volumes issued to readers of each occupation, and tables show- 
ing the books most in demand. From the latter item we are 
glad to see that science in its various departments comes in for a 
very fair share of attention. In April 1872 the Reference 
Library and the Art Gallery were thrown open to the public 
on Sunday afternoons, and to judge from the statistics, the 
privilege has been taken considerable advantage of, especially 
by those who have least time during the week for mental 
improvement. 
IN the last number of the Yournal of the Statistical Society is 
an interesting paper by Mr. F, Galton, F.R.S., on the Relative 
Supplies from Town and Country Families to the population of 
future generations. Mr. Galton took for the purpose of com- 
parison, from the census returns, 1,000 families belonging to 
Coventry, in which there are various industries, and where the 
population is not increasing, and 1,000 families from small agri- 
cultural parishes in Warwickshire. After careful comparison 
and calculation, based on ascertained data, Mr. Galton concludes. 
that the rate of supply in towns to the next adult generation is 
only 77 per cent., or, say, three-quarters of that in the country. 
In two generations the proportion falls to 59 per cent., that is, 
the adult grandchildren of artisan townsfolk are little more than 
half as numerous as those of labouring people who live in 
healthy country districts. 
THE Reports and Proceedings for the year 1872-3 of the 
Miners’ Association of Cornwall and Devon, contain some good 
papers, mostly of a practical nature, in connection with mininy. 
WE have received the Monthly Notices of the papers and 
proceedings of the Royal Society of Tasmania for 1870, 1871, 
and the half of 1872. A great part of them are occupied with 
valuable meteorological observations and statistics, and from the 
reports of the society’s meetings and the numerous papers printed 
in extenso on subjects connected with all departments of science, 
we judge the society to be in a healthy condition, As might 
naturally be expected, many of the papers are devoted to the 
practical aspects of science, to pisciculture, arboriculture, agri- 
culture, the rearing of sheep, &c. 
WE would recommend to anyone visiting Derbyshire, espe- 
cially the district around the Peak, Mr. Bates’s little ‘* Hand- 
book to Castleion and its Neighbourhood,” containing very full 
and well-compacted information on all the places of interest 
around. There is a useful section on the geology, mineralogy, 
and botany of the district, and we believe that Mr. John Tym, 
of Castleton, the publisher of the book, well known as a geolo- 
gist, will willingly give anyone who calls at his shop, informa- 
tion on the natural history of the district. 
WE would recommend to all Londoners who are at a loss how 
to spend an occasional holiday to procure the summer edition of 
Mr. Henry Walker’s ‘‘ Half-Holiday Guide,” which is wonder- 
fully cheap considering the quantity of matter it contains. It 
would take a few summers ‘of half-holidays to exhaust all the 
charming resorts around London he describes. The book also 
contains much useful information for the botanist, geologist, 
ornithologist, entomologist, and microscopist, as well as with 
regard to various sports. Mr. Walker should, however, cease 
to quote so much irrelevant verse, 
