Davis's Report on the Nautical Almanac. 333 
solute conditions of its usefilness and respectability. But every 
person of experience knows that neither such extensive computa- 
tions, nor the printing of so many figures, can be conducted with 
entire freedom from error; and to remedy this defect, inherent in 
such productions, the errors detected are printed and the corree- 
tions applied in the subsequent volumes, probably before the 
ormer come into general use. 
The calculations of the Nautical Almanac in reference to the 
sn, moony principal planets, &c., are in the case of each one of 
them, based upon our knowledge of their motions and the laws 
by which they are controlled, derived from the general theories 
of celestial mechanics, arid from observations which, while they 
test the truth of the general theory, lead to the discovery of new 
facts and data, to the detection of other laws, and to the inference 
of new generalizations 
The observations thus employed comprise all the calculations of 
good authority, which from age to age have accumulated in the 
tich treasury of astronomical science ; ending with the latest pub- 
lieations of existing obsetvatories, and going back to the begin- 
ning of authentic history. In order suitably to convey our know- 
ge of the laws governing the motions of the heavenly bodies, 
and regulating their more or less rapid change of place, and to put 
this knowledge in a form adapted to the wants and uses of the 
computer, numerical tables have been prepared of the sun and 
the planets separately, which constitute the abbreviated expres- 
sions of these laws. 
_ The numerical tables greatly facilitate the labor of computa- 
tions; they are the computer's tools of trade. * 
To construct these tables; to make, compile, and arrange these 
observations ; to discuss them; to discover and investigate the 
theories and laws; and to invent that kind of logic, the higher 
mathematics, by which alone such investigations can be profita- 
bly pursued and their results succinctly defined, have been the 
Sccupations in every enlightened age of the most illustrious genius 
and the most exalted talents. And a correct and well conducted 
astronomical ephemeris, which comes up to the latest standard of 
modern improvement and discovery, is to be regarded as the full 
exponent of all this haman thought and labor. tig 
it from this very compendious exposition of the scientific 
character of the “Nautical Almanac and Astronomical Epheme- 
tis,” of the intellectual basis on which it rests, it may be well to 
turn to an inquiry into its practical utility, into the manner in 
Which it has benefited mankind ; for knowledge is always instru- 
mental in promoting the best interests of humanity. 
“he primary motive for computing and publishing the Nantical 
Almanac, was to promulgate the luuar method for determining 
the longitude at sea, and to furnish the requisite elements and 
Bxcoxn Serizs, Vol. XIV, No, 42.—Nov., 1852. 43 
