10. The number of lunar distances given is very much increased.
Besides these principal alterations, there is a large number of minor additions, tend ing for the most part to save labour in calculation ; and the extent to which the results have been carried is materially enlarged. Any errata discovered in any mathematical tables which are generally or even occasionally of use, will be pub lished in the Nautical Almanac,' if com municated by the finder.
This country was forestalled in most of the important changes just mentioned, by the Berlin Ephemeris,' published under the superintendence of Professor Encke. Its predecessor, the' Astronomisches Jahr buch,' was conducted for fifty years by the celebrated Bode ; and was entirely remodelled by Encke in 1830. Of other works of the same kind, published on the Continent, those of Coimbra and Milan are among the most valuable; the latter was commenced in 1755, by M. de Camaris ; we have not been able to learn the date of the first establishment of the former.
The oldest national astronomical alma nac is the French Connoissance des Tems,' published at present under the superintendence of the Bureau des Longi tudes at Paris. It was commenced sa 1679 by Picard, and continued by him till 1684. It then passed through the hands of various astronomers, till 1760, when the conduct of it was given to La lande, who, besides other alterations, first introduced the lunar distances, which have been already alluded to. At pre sent the plan is very similar to that of the new Nautical Almanac,' with the addi tion of very valuable original memoirs which appear yearly. In fact we may say generally, that the original contribu tions to the various continental almanacs are among their most valuable parts ; and, as Professor Airy remarks, Reports of the British Association,' &c., p. 128, " In fact nearly all the astronomy of the pre sent century is to be found in these works," that is, in certain periodicals which are mentioned, " or in the Ephemerides' of Berlin, Paris, or Milan."
Next to the Nautical Almanac,' the private publication which is most entitled to notice as an astronomical almanac is White's Ephemeris,' a work which is nearly as old as the monopoly previously described. For many years past, this publication has given astronomical data sufficient to enable the seaman to find his latitude and time. The Gentleman's Diary,' commenced in 1741, and the Ladies' Diary,' in 1705, have power fully aided in keeping up a mathematical taste, to a certain extent, throughout the country, by annually proposing problems for competition : several, who have after wards become celebrated in mathematics, have commenced their career by the solu tion of these problems.
The duty on almanacs was abolished in August, 1834, by 3 & 4 William IV. c. 57. The stamp was fifteen pence on each almanac. The average number of stamps issued between 1821 and 1830 in clusive, was about 499,000 yearly, pro ducing an average revenue of about 31,000/. The largest number of almanacs stamped in any one year during the above period was 528,254 in 1821, and the smallest number was 444,474 in 1830; and in 1833, the year before the duty was abolished, the amount of duty was only 26,1641. The tax prevented the free competition of respectable publishers in almanacs, and tempted so many persons to evade the law, that nnstamped al manacs were circulated in as large numbers as those which paid the tax. It is stated in the Report of the Com missioners of Excise Inquiry that 200 new almanacs were published as soon as the duty was repealed, of some of which upwards of 250,000 copies were sold, although the old ones not only main tained, but, in some cases, doubled their circulation. The most marked effect of the repeal of the duty is perhaps the im provement in the character of almanacs.