with Bliss & Creighton patented balance,

This chronometer was made in the short period between the dissolution of Bliss & Creighton in 1853, and John Bliss (the elder)'s death in 1857. It has the Bliss & Creighton balance, patented in 1845 (patent #4135). The only difference between this balance and my Bliss & Creighton # 2076 is this has round compensation weights, whereas the B&C has wedge shaped weights, as does the one Creighton & Black balance I've seen. A testimonial letter (see below) in later John Bliss & Co. catalogs concerning John Bliss & Son chronometer 2485, the next one after this chronometer, indicate that no. 2485 was rated in New York Feb. 16, 1856. Chronometers were usually allowed to settle in for up to a year before being sold, so my no. 2484 was almost certainly made in 1855, and probably sold in 1856. 

JOHN BLISS & SON #2484 Box	JOHN BLISS & SON #2484 Box open
JOHN BLISS & SON #2484 Dial, silvered with gold hands 3-3/4 in. diameter	JOHN BLISS & SON #2484 Mechanism compare spotting with the other two chronometers.

This chronometer has the "H" shaped balance (as opposed to the standard Earnshaw "Z" balance) patented by John Bliss & Frederick Creighton in August of 1945. Physically this resembles the modern "Integral" balance, but the materials used are different, so the operation is not the same. The patent, #4135 dated Aug. 4, 1845, was probably at least one subject of the lawsuit between the former partners after they split up. Both of the successor firms, Creighton & Black and John Bliss & Son, used the balance in their chronometers. In addition to the "H" shape of the balance, designed to correct for middle temperature error, the patent also had a claim for "the application of a second balance spring above, below, or inside the single balance spring heretofore in use...to insure a more equal rate of going..." by averaging out any physical inequalities in the two springs. This second claim did not deal with the middle temperature error, and may never have been fitted to any chronometers. All Bliss & Creighton chronometers I've seen from SN#1036 onward have the "H" balance, but I've never seen the double balance spring.

Testimonial for John Bliss & Son chronometer no. 2485 from the 1877 edition of the Abridgment of the Nautical Almanac and Tide Tables published by John Bliss & Co.:

Messrs. John Bliss & Son:

Gentlemen: I desire to add my name to the large number of those who have borne witness to the superior performance of your Chronometers, by testifying to the running of Chronometer J.B.&S., No. 2485, used by me on board the steamship Tennessee, during her five last trips.

Below I give you a copy of your rates which I have invariably found correct:

Rated	N.Y.,	Feb 16, 1856,	..............................	Gaining	0	sec.	1	tenth.
"	"	Mar. 29, 1856,	..............................	"	0		0
"	"	May 10, 1856,	..............................	"	0		3
"	"	June 21, 1856,	..............................	"	0		0
"	"	Aug. 8, 1856,	..............................	"	0		0

I would add here that two years ago I used a Chronometer of your make, which I think was quite as good as the above.

Yours Truly,

CHAS. M. WEBBER

Late commanding U.S. Mail Steamship Tennessee