420 
POPULiR SCIENCE REVIEW. 
less than ninety-seven of these bodies have been discovered; or, on an 
average, upwards of four per annum. 
A new Driving-clock for Equatorials. — Mr. Cooke has been successful in 
devising a driving-clock in which the regulator is the ordinary vibrating 
pendulum. The difficulty in this case is to convert the jerking or intermit- 
tent motion produced by vibrating pendula into an uniform motion, which 
can be available with little or no disturbing influence on the pendulum 
itself, when the machine is subject to the varying frictions and forces which 
have to be overcome in driving large equatorials. This difficulty Mr. Cooke 
appears to have successfully overcome. He states that the uniform rotatory 
motion obtained by a clock constructed on his plan appears to be perfectly 
satisfactory, so far as experiments can be made by applying widely different 
weights and comparing the times with a chronometer.” As there is no other 
means at the mechanician’s command for obtaining good time-keeping, which 
is so accurate as the vibrating pendulum, it is important that this means 
should have been rendered available to the astronomical observer. 
The approaching Transit of Mercvry. — On the morning of November 5 
the sun will rise with Mercury on his disc. The transit of the planet will 
end two hours after sunrise. 
The November Shooting-stars are not likely to be favourably seen this year 
in England ; in fact, we need hardly expect to see them again until the year 
1870. Even then the display is not likely to be very brilliant, as the part 
of the system through which the earth will then pass will be much less 
densely strewn with meteoric bodies than the part passed through in 1866. 
The epoch of maximum display this year is likely to occur dmlng midday 
in England and in most parts of Europe. 
Sun-spot visible to the naked Eye. — An enormous sun-spot was distinctly 
visible to the naked eye on August 14. We are not aware that any 
European observers noticed the circumstance ; but the owner of Fern Lodge 
Observatory, Palisades, Eockland, county New York, who has supplied an 
interesting picture of the spot, announces that it could be clearly seen with 
the naked eye. 
Fall of Meteorolites in Piedmont. — A somewhat remarkable fall of meteoro- 
lites is recorded, in Comptes Rendus for August 3, as having taken place in 
Piedmont on February 29, 1868. Several large masses of meteoric matter 
would seem to have burst, the fragments falling over an extensive ar»a. On 
analysis the fragments were found to contain silica, sulphur, phosphorus, 
copper, metallic iron, oxide of iron, nickel, manganese, chromium of iron, 
alumina, magnesia, potash, lime, and soda. 
BOTANY. 
The Tendrils of the Cucurbitacece. — Those who are interested in what used 
to be styled vegetable morphology should read an excellent memoir by M. 
Lestiboudois, On the Homologies of the Tendrils of the Cucurbitacese.” This 
botanist lays down the proposition that the tendrils in their order are modi- 
fied leaves, and the evidence he adduces in support of it relates both to the 
