iv PREFACE. 



rangement may be the most conveniently understood from the table of 

 contents prefixed to the catalogue; and the method of classing the 

 subdivisions and titles, which become more and more particular, has 

 been as much as possible such, that if sufficient information cannot be 

 found under the head to which the subject immediately belongs, there 

 may always be a chance of obtaining it from some more extensive 

 work,under the last head, of a more general nature, which may be found, 

 in the catalogue, by looking back for a change of type, or in the table 

 of contents, by recurring to a column situated one degree more to the 

 left. On the other hand, in order to faciUtate, in some measure, the la- 

 bour of selection, such works, as appeared to possess superior merit and 

 originality, have been distinguished by asteriscs; and those, on tlic con- 

 trary, that have been thought either erroneous or unimportant, have 

 been marked with an obelise. It must not however be understood, that 

 all the other works mentioned are considered as deservins: neither com- 

 mendation nor censure, since with respect to the greater number of 

 them the evidence must necessarily be imperfect. The extracts occa- 

 sionally inserted, as well as the original remarks which are sometimes in- 

 troduced, are not so much intended for the general reader, as for those 

 who make any single department their particular study; many of them 

 being only brief hints, which may serve to direct their attention to a fur- 

 ther pursuit of the subjects. In the mathematical and astronomical 

 parts, all references to the transactions of foreign societies have in gene- 

 ral been omitted ; partly because they would have been too numerous for 

 insertion, and partly because they may be found at large in the copious 

 works of Murhard and of Reuss. The references to periodical pub- 

 lications have been continued, where it was possible, to the beginning 

 of the year 1805. 



For the convenience of those who have access to the libraries of the 

 Royal Institution, of the Royal Society, of its most liberal and illustri- 

 ous President, and of the British Museum, such works as are to be 



