148 REPORT — 1855. 



On Improved Monographic Projectmis of the World. 

 By James Gall, Jim., Edinburgh. 



Cylindrical maps alone can represent the whole world in one diagram. There 

 are only three featnres in which a cylindrical map can be accurate : — 1. in Orienta- 

 tion ; 2. Polar distance; and 3. Proportion of area ; biitif one of these be obtained, the 

 others must be sacrificed. The best projection is that which will divide the errors, 

 and combine the advantages of each. Mercator's projection sacrifices Form, Polar 

 distance, and Proportionate area, to obtain accurate orientation for the navigator ; 

 Avhereas, to the geographer, Form, Polar distance, and Proportion of area are more 

 important than Orientation. 



Polar distance is obtained by making the degrees of latitude equal. 



Proportion of area is obtained by projecting the degrees of latitude orthographically. 



In these two projections orientation can be correct at only one line of latitude; but if 

 we select the 45th degree of latitude, and make the orientation correct at that line, 

 the error is halved on each side and the distortion less offensive. 



The projection which unites all the advantages of the three, in the best proportion, 

 is obtained by projecting the degrees of latitude stereographicaliy, and selecting the 

 45th degree of latitude as the line of correct orientation. It will possess the followhig 

 advantages : — 



1. It gives a more accurate representation of geographical forms. 



2. It gives a representation of the ivhole world, including the poles. 



3. It represents polar distance and proportionate area better ; and 



4. It saves 25 per cent, of the space occupied by Mercator's. 



Note. — There is no formida by which Mercator's chart may be projected ac- 

 curately, the orientation of each degree being obtained by calculation ; but an 

 approximation may be obtained (up to the 85th degree) by projecting the latitudes 

 from a point behind the quadrant, nine degrees higher than the base, and one-third 

 of the radius distant from the centre. This approximation is so close, that it cannot 

 be distinguished except by careful measurement, and is of use for particular pur- 

 poses. 



An Accotmt of the Exploration of the Isthmus of Darien, under Capt. 

 Prevost, jR.ZV. By J. M. Inskip. 



The greater part of the country was extremely wooded, so much so that the party 

 had to cut their way through it, sometimes only being able to advance at a rate of 

 about two miles to two miles and a half a day; and otiier parts were extremely swampy, 

 presenting almost equal difficulties to the explorers. He gives an opinion, that, before 

 any complete survey can be made, it will be necessary either to conciliate or subdue 

 the Indians, and that the construction of a canal across the isthmus will be a work 

 alike of great difficulty and ex])ense. A railway, however, may be constructed with- 

 out probably any greater difficulties than exist in many parts of England. 



Extracts from Letters dated Pungo, Andongo, and St. Paid de Loanda, 

 describing his Journey across Tropical Africa. By Dr. Livingston. 



These papers speak of the great value of Angola and other Portuguese possessions 

 jn Africa, commercially, more especially to the British, by whom they have been long 

 neglected, principally, it would appear, from the slave trade having interfered with 

 legitimate commerce, which, however, is now being rapidly developed ; the export 

 slave trade having been altogether abolished, and the condition of the domestic slaves 

 very much ameliorated. 



On the Preadamitic Condition of the Globe, By Prof. MacDonald. 



T7ie Geographical and Historical Results of the French Scientific Expedition 



to Babylon. By Dr. Julius Oppert. 



Dr. Oppert stated that he had spent two years on the site of Babylon, examining 



the cuneiform inscriptions on the bricks and stone slabs. Babylon covered rather 



more than an area of 200 square miles, being about two and a half times as great as 



