GREENWICH OBSERVATORY. 
281 
evidence is given of the connexion of results thus obtained 
with other cosmical elements. I think that these considera- 
tions exclude measures of double stars at the Royal Observa- 
tory, but they leave an opening for the scrutiny of nebulae, 
planets, &c., and possibly (but I speak in doubt) of solar spec- 
troscopy. But I have no doubt that they fully sanction the 
undertaking a continued series of observations of solar spots. 
The character of the Observatory would be somewhat changed 
by this innovation, but not, as I imagine, in a direction to 
which any objection can be made. It would become, pro 
tanto , a physical observatory ; and possibly in time its opera- 
tions might be extended still further in a physical direction.” 
Upon the effect of these statements it would be premature 
to speak. It is, however, generally understood that the Board 
decided upon the advisability of extending the Observatory 
system so far (for the present) as to include regular photo- 
graphic record of solar spots and systematic solar spectroscopy. 
The Visitors are an intermediary body : before full effect can 
be given to their decision the Treasury must be appealed to for 
funds for the first cost of instruments and the running expense 
of an increased personal staff. 
Chronometers have such a direct connection with navigation 
and sea-longitude, that not unnaturally Greenwich has been 
identified with the testing of these instruments from their in- 
vention to the present day ; and now it is the chief depot for 
Government marine chronometers. All business of their pur- 
chase, trial, and repair, is transacted at the Observatory ; and 
usually about 200 chronometers are there under rating for issue 
to H.M. ships. Every year there is a competitive trial open to 
all makers, during which the chronometers are exposed to a 
wide range of temperature : four or six of the best instruments 
are each year purchased at good prices, and it is doubtless to 
these trials and to the general Government patronage of the 
trade that the supreme excellence of British chronometers is 
due. 
Into the department of Time and its distribution we need 
not enter further than to say that a signal ball is dropped at 
one o’clock daily at the Observatory, and another ball at Deal 
is dropped by direct current from the Observatory ; and that 
every hour accurate electric signals go forth from Greenwich, 
which are variously distributed over the country ; one of them, 
that at 10 a.m., passing through well-nigh all the important 
telegraph lines in England. This department of the Observa- 
tory was, however, fully described in a previous number of the 
Popular Science Review (October 1870). 
A magnetical and meteorolgical department was estab- 
lished in 1 840, and till 1 847 eye-observations of its instruments 
