On the Sea and Land Rates of Chronometers. 121 
Arr. XXII.—On the Sea and Land Rates of Chronometers; by 
Parxinson & FrRopsuHam. 
(Republished in this Journal by request.”) 
TO THE EDITOR OF THE NAUTICAL MAGAZINE. 
Str—An article in your Magazine for May, entitled ‘“ Magnetic 
experiments on Chronometers,” by Messrs. Arnold and Dent, has 
appeared to us, and to several others of our distinguished contem- 
poraries in the profession, to require some notice, as its effect may 
be, to lead persons unacquainted with the subject to form very erro- 
neous notions as to the degree of perfection which the art of chro- 
nometer-making has reached. Indeed, if chronometers in gener- 
al, as sent from the hands of respectable makers, were the imper- 
fect sort of machines which those appear to have been on which 
your correspondents have experimented, they would ill deserve the 
confidence which nautical men have long seen reason to place in 
them. 
We remark in the first place, on the striking change of rate which 
your correspondents represent as caused by the (we presume care- 
ful) removal of chronometers from London to Greenwich, amount- 
ing to as much as two seconds per diem, that it is not at all in accor- 
dance with our experience. We are constantly in the habit of taking 
chronometers from our house of business in town to our private resi- 
* 4’Change Alley, London, December 20, 1833. 
TO PROFESSOR SILLIMAN. 
Dear Sir.—We respectfully take leave to enclose you a paper entitled Land and 
Sea rates of Chronometers, which we have thoughtit necessary to publish in answer 
to a paper which appeared ina periodical entitled Nautical Magazine, and contained 
to our ideas very erroneous opinions. 
As it is asubject which we believe concerns every maritime nation and none more 
than your own—we have to request that you will do us the favor of inserting it in 
your valuable Scientific Journal. Our object in wishing to give this paper the most 
extended circulation, is, that we believe it might destroy the confidence of the Nau- 
tical man in one of the most important inventions for the benefit of Navigation; and 
we feel assured that many hundreds of your most intelligent navigators from their 
experience can bear witness that owr Chronometers are not subject to the change 
of sea and land rates (which would render them useless for navigation) as stated to 
exist in the Chronometers of Messrs. Arnold & Dent. 
We remain sir, your very obedient servants, 
for Parkinson & FropsHam. 
Joun FRopsHam. 
Vou. XXVI.—No. 1. 16 
