CHRONOMETERS AND ELECTKICAL CLOCKS. 
503 
in a ship’s chronometer” may cause a wreck with all its disastrous results ; 
loss of life and property at sea, destitution and mournful misery on shore ! 
Surely, then, the man of science who provides the means of obviating such 
terrible evils as these is entitled to the gratitude and respect of Ms fellow 
men! 
But the details of those patient and laborious investigations of which the 
world at large derives the practical benefit (often without knowing the source 
from whence it proceeds), are frequently clothed in such tecMiical guise that 
a record of them would be unintelligible to a vast number of persons whose 
curiosity and interest would prompt them to seek such information ; and 
tMs is another reason why the vigils of the worker often remain unknown 
and unrecorded, except for the benefit of a privileged few ; and consequently 
his trials and difficulties do not meet with that reward wMch the world 
would be willing to bestow. 
Mow, although we do not mean to say that these observations apply in 
their entirety to the instance before us— for the labours of Mr. Hartnup, the 
able representative of Astronomical Science in Liverpool, are well under- 
stood and appreciated, and their practical results force themselves npon the 
notice of all who take the least interest in the subject — we may still 
adduce this as an example of what may be done by patient and arduous toil, 
without being fully recognized by the public at large ; for we venture to 
affirm, that, many as are Ms friends and supporters who will have carefully 
perused his interesting pampMet, they are far outnumbered by those who 
will have laid it aside without at all inquiring into its importance or the 
records of progress which it contains. 
Possibly they may have been so unfortunate as to open it at pages 10 and 
11, and, terrified by the long array of figures, they may have mistaken it 
for a table of logarithms, or something equally uMntelligible to the mind 
commercial ; but had they turned over another page they would have found 
that to Mr. Hartnup they owe the accuracy of their gold timepieces, and that 
his labours are intimately associated with all their mercantile concerns. 
And now, what does this pamphlet really tell us 1 As the expositors of 
Science, standing between the abstruse and popular inquirer, we will endea- 
vour, after our own fashion, to interpret its contents. 
The Liverpool observatory is placed under the direction of John Hartnup, 
Esq., F.R.A.S., a well-known and highly esteemed astronomer and meteor- 
ologist, and perhaps Ms most important duty, one which cannot be too MgMy 
estimated, is the correction of ships’ chronometers by the means of instru- 
ments and appliances placed at his disposal by the Mersey Dock Board. 
Upon the accuracy of a ship’s chronometer may hang the lives of thousands, 
the issues of peace and war, the fate of individuals and of nations, for it is 
now employed not only to indicate the hour of the day, but also for a much 
more important purpose, for “ if such clocks or rvatches could be made to 
show the correct Greenwich time at sea, then the mariner, on finding 1ns 
local time by the position of the heavenly bodies, would know Ms longitude 
from Greenwich.” We must presume that the reader understands the 
rationale of tMs statement, and he will perceive that an error of a few 
minutes in the captain’s timepiece may take him out of 1ns course, delay the 
delivery of Ms despatches, or lead his ship to destruction. For the purpose 
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