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THE POPULAR SCIENCE MONTHLY. 



cates Paris, for example, can be fixed for the moment in these 

 splits, as an aid in tracing the railway lines and measuring the 

 distances between the several cities. Laas d'Aguen, in 1847, in- 

 vented a kind of map which could be reproduced by printing. 

 Previous to his, MM. Pignier and Boher Keller impressed maps 

 in relief on thick paper, in which the meridians and parallels were 

 represented by fine threads, boundaries by round points, mountains 

 by large oval points, and seas and lakes by striae. This method 

 was adopted by the Moon Society in England and by the British 

 and Foreign Blind Association, the first of which published atlases 

 of terrestrial and celestial maps. M. Kunz, of Illzach, and M. 

 Abel Pifre, of Paris, have published some most excellent maps, 

 the former of which are very cheap, and the latter, the best of 

 their kind, high. 



M. Ballu took up some years ago the idea of Sanderson's tablet, 

 for making arithmetical calculations. It is composed of a plaque 

 divided by prominent metallic lines into many little squares 

 pierced by nine holes arranged in threes, and numbered from 1 to 

 9 (Fig. 5, No. 1, 1'). Pins may be inserted into these holes, the 



Fig. 6.— Plate of the Macler Machine. 



rounded heads of which project above the surface of the plaque, 

 and indicate the figures from 1 to 9, according to the number of 

 the hole they occupy. The system is simple, but it takes a con- 

 siderable time to learn it. In Taylor's tablet, the metallic plate 

 is pierced with stellated octagonal holes, in which square pins 

 with beveled ends are set, one of the ends being smooth and the 



