6oo THE POPULAR SCIENCE MONTHLY, 



any one as soon as he observed by means of the camera the pres- 

 ence of a hostile vessel within the limits of any of the circles marked 

 upon his white table. 



In the American War of 1860, the electric torpedo, invented but 

 two years before, played a most conspicuous role^ and formed indeed, 

 with the use of big guns and monitor iron-clads, one of the most im- 

 portant features of the struggle, at any rate from a scientific point of 

 view. The war of 1866, when the Austrians suffered such a terrible 

 defeat at the hands of the Prussians, will long be remembered as a 

 combat between the old muzzle-loading rifle and the breech-loader, in 

 which the latter was victorious. The Franco-German struggle of 

 1870, again, though marked by the employment of no special arm, if 

 we except the mitrailleuse, was assisted by important applications of 

 science ; to wit, the reproduction, by means of photo-lithography, of 

 the French ordnance maps and plans, Avhich were distributed in thou- 

 sands thi'oughout the German army, and the establishment in France 

 oila jyoste aerienne to communicate with the besieged garrison of Paris. 

 The regularity with which the mails left Paris par ballon monte must 

 still be fresh in the memories of our readers, the publication of corre- 

 spondence from the French capital being maintained in our journals 

 during the whole period of the investment. From September 23d to 

 January 28th, when Paris was practically cut oiF from the rest of the 

 I'epublic, no less than sixty-four balloons left the city with passengers, 

 mails, and pigeons, and of these only three were lost, while five were 

 captured. The return-post by " homing pigeons " was hardly so regu- 

 lar, but nevertheless half the number of dispatches given in by corre- 

 spondents at Tours and elsewhere, or in other words 100,000 mes- 

 sages,, were by the unflagging energy of the postal authorities carried 

 into the beleaguered capital. The dispatches, most of them as brief as 

 telegrams, were distinctly printed in broad sheets and photographed 

 by the aid of a micro-camera ; impressions upon thin, transparent films 

 were then taken and rolled in a quill attached to the tail of the winged 

 messenger which was to bear them into Paris. Arrived at tlieir des- 

 tination, the tiny photographic films were enlarged again by the 

 camera, and the disi^atches, being once more legible, were distributed 

 to the various addresses. 



The present Russo-Turkish War cannot well be less interesting 

 than those that have so recently preceded it, and we may especially 

 point out two directions in which fresh examples of scientific war- 

 fare will probably manifest themselves in connection, namely, with 

 the cavalry pioneer and the Whitehead torpedo. Both of these will 

 probably be seen in warfare for the first time, and before many days 

 are past we may hear of their doings in action. 



The cavalry pioneer must not be confounded with the Prussian 

 Uhlan who played so conspicuous a part in the last war. The ubiqui- 

 tous Uhlan, terrible as he was, did not work the injury which some of 



