ON THE PROGRESS OF SCIENCE. VII 



the telescope, the effect being assisted by the tinted paper on which 

 the engravings are printed. Mr. Bond has, moreover, taken into his 

 narrative the results obtained by other observers in all parts of the 

 world, and has thus produced the most complete history of Donati's 

 Comet that has yet been written, and, we may say, the most attrac- 

 tive. 



The publication of a splendid work, in large folio, entitled " The 

 Satellite," has been commenced in London, by Dr. A. D'Orsan ; the 

 chief feature of which is the photographic delineation of the moon. 

 The whole is to be finished in twelve parts. The following are ex- 

 tracts from the preface : " Detail being my principal object, large 

 photographs of various separate spots are given, in addition to those 

 which, taken at different periods of lunation, contain at once many 

 spots and regions, and represent them under different aspects. From 

 the guidance and instruction these afford, together with the fact of 

 their presenting one and the same spot under various degrees of illu- 

 mination, and consequently diverse appearances, elaborate drawings, 

 founded on many years' observations, will be given, exhibiting ap- 

 proximately the real outline of each respective spot. . . Those photo- 

 graphs of the various lunar parts that have been taken at one and 

 the same period of lunation are also joined together, and thus cor- 

 rect maps are given of the several phases. . . The photographs are 

 all on a scale never before executed, probably never before at- 

 tempted." 



School maps, as commonly printed, have either so many black lines 

 as to be scarcely legible, or so few as to afford but scanty information 

 to the student. Nor need one wonder at this defect. The text which 

 a map should yield is so various, first, as to the visible nature, 

 the shape of country, the hills and valleys, the lakes and rivers, the 

 woods and plains; next, as to the visible work of man, the cities 

 and towns, the castles and fortresses, the ports and harbors, the roads 

 and railways and canals, the mines and quarries and sea-works ; then 

 the political facts, such as the division into states, counties, and 

 towns, that it is found impossible to indicate all these facts, without 

 crowding, on a single sheet. To obviate these difficulties, Messrs. 

 Longman & Co., the well-known London publishers, have recently 

 brought out maps on England and Wales on a new plan ; L e., that 

 of treating each group of facts on a separate sheet. It is claimed that 

 in this way, and in this only, the great end of clearness is attained. 



The most important event in the scientific and industrial history of 

 the past year was undoubtedly the Great International Exhibition of 



