POPULAR MISCELLANY. 



119 



The Sugar-Beet in North Carolina. By A. 

 Ledoux. Raleigh: Farmer and Mechanic print. 

 Pp. 50. 



The Salt-eating Habit. By R. T. Coburn. 

 Dansville, N. Y. : "Austin, Jackson & Co. print. 

 Pp. 29. 



The Star-Finder, or Planisphere, with Mov- 

 able Horizon. New York : Van Nostrand. 



POPULAR MISCELLANY. 



The Growth of Photography. At one 



of the public lectures recently given under 

 the auspices of the New York Academy of 

 Sciences, Prof. Charles F. Chandler sketched 

 the progress of photography during the last 

 hundred years. The first authentic record 

 of pictures made by solar agency he finds 

 in Cooper's " Rational Recreations," pub- 

 lished in 1774, where an account is given 

 of the marking of bottles by silver salts. 

 Next came Scheele's experiments on the 

 effect of exposing to light paper sensitized 

 by the same salts. The first genuine sun- 

 pictures were probably produced by Bolton 

 and Watt, who were followed by Humphry 

 Davy and Wedgwood. Still, down to the 

 beginning of the second quarter of the 

 nineteenth century, photography had not 

 advanced beyond the stage of producing 

 images of plant-leaves laid on sensitized 

 paper, and exposed to light. These images, 

 crude as they were, soon disappeared on 

 continued exposure of the paper to the light, 

 for as yet no means of fixing the photograph 

 image had been discovered. Niepce stud- 

 ied the subject experimentally for nearly 

 fifteen years, without any very encourag- 

 ing results, but in 1824 he associated with 

 himself Daguerre, who in 1839 announced 

 to the world his discovery of a method of 

 producing permanent sun - pictures. Dr. 

 Draper, of New York, added sundry impor- 

 tant improvements to Daguerre's method. 

 Fox-Talbot produced the first silvered-pa- 

 per photograph, which was the germ of the 

 modern sun-picture. The great develop- 

 ment came in 1841, when Schonbein dis- 

 covered gun - cotton. Cotton, he found, 

 when exposed to nitric acid, becomes ex- 

 plosive, and soluble in a mixture of alcohol 

 and ether. The discovery of this latter 

 property was the foundation of the com- 

 mon photographic process, where a film of 

 collodion, sensitized by silver iodide, pro- 

 duces the " negative " image, from which 



thousands of pictures may be struck off. 

 It was stated by Prof. Chandler that Albert, 

 a photographer of Munich, and Edward 

 Bierstadt, of New York, are engaged in 

 perfecting a process for printing photo- 

 graphs in colors. 



The Development of Botanical Science. 



The progressive development of botanical 

 science is forcibly exhibited by the Belgique 

 Horlicole, in a numerical statement of the 

 different species of plants named in sundry 

 ancient documents, and now ascertained by 

 botanists. Thus, in the Bible, we are told, 

 about fifty plants are clearly determined, 

 while about as many more are mentioned in 

 more general terms. Hippocrates mentions 

 234 species, Theophrastus about 500, Dios- 

 corides over 600, and Pliny 800. In the 

 sixteenth century Conrad Gerner names 

 800, Charles de l'Escluse 1,400, Dalechamps 

 2,731, and Gaspard Bauhin 6,000. In 1694 

 Tournefort describes 10,146 species. He 

 was the first to class the species of plants 

 into genera, of which he reckoned 694. In 

 the eighteenth century Linne defined 7,294 

 plants, distributed in 1,239 genera. In 

 1805 Persoon's " Synopsis Plantarum " in- 

 cluded nearly 26,000 species, and in P. de 

 Candolle's " Elementary Theory of Botany " 

 30,000 species are said to be known scien- 

 tifically. Stendel's " Nomenclator Botani- 

 cus" (published in 1824) contains 78,000 

 names of plants. Loudon's " Hortus Bri- 

 tannicus" (1839) enumerates 31,731 species 

 in 3,732 genera. According to Endlicher 

 (1840), there were 6,895 known genera in 

 the vegetal kingdom, which number is in- 

 creased to 8,931 by Lindley in the year 

 1853. In 1863 Bentley estimated the 

 known species at 125,000. The Belgique 

 Horticole thus classes the species now 



known : 



60,000 dicotyledons, 



20,000 monocotyledons, 



40,000 cryptogams, 

 or, in all, about 120,000 species distributed 

 among 8,000 genera. The species actually 

 cultivated number 40,000, and these are 

 true botanical species, not simply races or 

 varieties. 



Facts abont the So-called Rain-Tree." 



For some months there has been circu- 

 lating in the newspapers a notice of a tree 



