1816] Scientific Intellizence. 1G 
VI. Influence of Galvanism ; in an Extract of a Letter from Dr. 
Redman Coxe, Professor of Chemistry, Philadelphia, 
The extensive influence of galvanism throughout “nature is so 
extraordinary, that we cannot wonder if we think we perceive 
traces of its agency in.cases where it has never vet been proved or 
suspected to exist. I am led to this observation from some reflec- 
tions that have lately oceurred to my mind, as to the principles of de- 
struction in watches and timepieces. When two dissimilar metals 
are brought together, with any intervening fluid, will not galvanic 
action ensue? If so, do we not immediately recognise its agency 
in the cases above mentioned? Are not the pivots of the poe 
(iron or steel) revolving in their small caps of brass, lubritated 
with oil? How, then, can galvanism fail to be excited? It is 
true the masses in contact are minute, but in a like degree will be 
the energy of the action produced. Now if i am correct, does it 
not follow that, however accurate a watch may he adjusted, ‘and 
however well it may for a time continue to go; sooner or later the 
oxide produced must obstruct or annihilate the motion of its wheels; 
and hence (independently of occasional influence from magnetism 
in any part of the steel work) a watch must necessarily in a few 
years become of no use as a timekeeper. Inthe case of a common 
watch this is perhaps of little moment, excepting so far as regards 
the expense of the individual; but in chronometers at sea, intended 
to subserve the purposes of navigation, this must be regarded as of 
high importance. A great deal is ascribed to bad oil, and to other 
causes, all of which may have their influence; but let the oil be 
ever s0 free from raucidity, if galvanism is active, deterioration must 
ensue. Can this cause be any how obviated, supposing the principle 
to be correct? I know of no mode but that of making the pivots 
themselves of the same material as that they play in; and as they 
are so small, it seems to me this may easily be effected by tempering 
them properly. At any rate, I conceive the circumstance to be of 
sufficient importance to awaken the attention of those more imme- 
diately interested in the construction of this useful machine. 
VI. On the usual Mode of Fixing the common Four-glass at Sea. 
By the Same. 
Another point which occurs to my mind, and which I do not 
recollect to have seen in any author, is the probable influence 
which, on a great scale, may arise to the perfect notation of time 
at sea, by the usual mode of fixing the common hour-glass. _ Is it 
not probable that during heavy gales the violent shocks sustained by 
the ship from the waves may momentarily occasion a sudden check 
to the regular passage of the sand through the small opening of the 
glass? However trifling in itself, the effect repeated frequently 
would certainly tend to prolong the apparent period of 24 hours, 
and thus cause an error in the ship’s way. And when neither sun, 
moon, nor stars, enable an observation to be made, by which such 
