546 THE POPULAR SCIENCE MONTHLY. 



decree read, "assisted at meetings organized for purposes con- 

 trary to the institutions of the country/' Quetelet was discom- 

 moded by the action of the Government, and did not conceal the 

 fact. Houzeau continued, however, to take part privately in the 

 work of the observatory for a few months, till he started on a 

 tour in Germany, Switzerland, and France. Sojourning at Lyons 

 from the following February till May, he occupied himself with 

 the preparation of several works, among them two treatises on 

 Meteorology, which appeared afterward in the Encyclope'die popu- 

 laire. In May, 1850, he settled in Paris, where he resided for five 

 years, devoting himself principally to study. He was an indus- 

 trious taker of notes, which related, not to science alone, but to all 

 branches of human activity, and embraced anecdotes and jokes. 

 He assisted M. d'Abbadie, of the Institute, in arranging the scien- 

 tific observations which he had made in Ethiopia. He interested 

 himself much in optical telegraphy. In conjunction with his 

 brother he made experiments at Paris and Mons to learn if the 

 light of the flashing of powder at one place could be seen at the 

 other. Of course, these experiments were not successful, for such 

 lights could not be seen at so great a distance. Some time after- 

 ward communication by the electric cable between England and 

 France was interrupted, and Houzeau proposed to the English 

 Cable Company to use a system of optical signals. Experiments 

 were determined upon between Dover and Calais, but were stopped 

 by the order of the French Government, declaring that such work 

 should be done only by agents of the state. They were under- 

 taken again in England, where this kind of interference could not 

 take place, between Southend and Whitstable. The first experi- 

 ments were successful, but the populace, excited by so much 

 night- work with fires, and fancying that the oyster crop would be 

 damaged by them, mobbed the experimenters and stoned Hou- 

 zeau's lodgings. 



The essay on the Physical Geography of Belgium (1853) was 

 the first book, M. Lancaster says, in which Houzeau " gave the 

 measure of his force as a man of science and a writer, and in 

 which one could perceive the whole extent and variety of his 

 knowledge, appreciate his expository talent, and enjoy the charm 

 of his sober, clear, and elegant style." He had been collecting ma- 

 terials for it for ten years, and in doing so made the best use of his 

 pedestrian excursions. The book is possessed of an interest that 

 does not pall for an instant in the reading, and is described by M. 

 Lancaster as one of the most remarkable works that can be cited. 

 An important paper in the same line was a study of the influence 

 by which the peculiar features of the relief of Belgian topography 

 had been produced. In 1854, through the influence of his friend 

 and former colleague, Liagre, Houzeau was temporarily commis- 



