of Nautical Astronomy. 355 
log, and the compass, had been properly attended to ; it ought 
to be examined whether the ship’s place had been determined 
by appropriate observations on every suitable occasion; whether, 
when observations of the sun for the latitude could not be ob- 
tained, their place had been supplied by observations of the 
moon or some other celestial object ; whether the variation of 
the ship’s compass had been determined by actual observation ; 
and whether such observations as had been made for the longi- 
tude, appeared to have been made in a satisfactory manner. 
If the log of every ship were thus subjected to review, we should 
soon see the masters of British merchantmen as much distin- 
guished for their science as they are now for their seamanship. 
A few years will introduce into efficient situations in the mer- 
chant service, many individuals whose opportunities of acquiring 
professional information, while they have been greater than many 
of their predecessors enjoyed, have also been assiduously im- 
proved. It is to be hoped that, while by pursuing an upright 
and manly course of conduct they will secure the esteem of all 
with whom they may be connected, the effect of their example i in 
exciting a better spirit among their brethren will not be incon- 
siderable. 
But unless some decisive general measure be adopted by those 
whose interests are so essentially connected with the state of 
nautical science, it will be a considerable time before the effect 
of example, or the efforts of isolated individuals, however intel- 
ligent or influential, will produce a material change in the habits 
of so large a body of men. 
It cannot, however, be too frequently repeated, that to acquire 
a thorough practical knowledge of every useful branch of nautical 
science, neither much time nor great talent is requisite. Those 
seamen, therefore, who may cuntinue to content themselves with 
the clumsy, unscientific practice of former ages, can have no 
rational apology to offer to the public. In what way they may 
excuse their conduct to themselves, it is of little importance to 
conjecture. 
LXXII. ikon of piece ison Pe various British Stand- 
ards of linear Measure. By Capt. Henry Karer, F.R.S. 
&e. 
[Concluded from p. 298.] 
I; may be seen inthe former part of this paper, that the tem- 
perature at which the points were laid off on Mr. Ramsden’s 
bar from the brass scale, was 54°; consequently, the observed 
lengths of the brass seales and 40-inch bar, must be reduced to 
this temperature. ‘The expansion of one foot of General Roy’s 
scale 
