Ml si:iM Xfr/'h's 



247 



would require hours or clays. To Abbe Keue 

 Just ITaiiy we are indebted for the discovery 

 upon which the science of crystallography is 

 based. One day he accidentally dropped a 

 hexagonal crystal of caicite (carbonate of 

 lime) and his keen observation noted in a 

 moment that when the crystal broke it 

 parted or cleaved into rlioinbohedrons, and 

 that these wduld luciik into rhondiohedrons 

 (id infinitum. lie ascertained that these 

 cleavage forms were always the same in the 

 same mineral; and from the fact that cer- 

 tain substances h.-nc a 

 constancy of crystalline 

 structure the world over, 

 more especially in the 

 cleavage, he established 

 the jirinciple tliat the 

 identity of a mineral al- 

 ways could be determined 

 by its crystalline form. 

 Thus caicite is always 

 rhombohedral ; the dia- 

 mond is octahedral; and 

 others in like manner. 

 Furthermore, when cer- 

 tain minerals crystallize 

 in the same system, some 

 slight peculiarity on the 

 surfaces or striations on 

 the side will aid in iden- 

 tifying just what the 

 mineral is. The study of 

 crystallography, there- 

 fore, was never more im- 

 portant than at the pres- 

 ent time, when, because 

 of the constant search for 

 war minerals, it is most important that de- 

 termination of these minerals be made 

 rapidly. 



Mr. B. T. B. Hyde has presented to the 

 library of the American Museum a large 

 number of the original plates of J. O. West- 

 wood "s Arcana Entomologica; or illustra- 

 tions of new, rare, and interesting Insects, 

 published in London in [1841] -1845, in two 

 volumes. 



The large Florida reptile group, in a dark- 

 ened gallery on the second floor of the 

 American Museum, constructed under the 

 direction of Miss M. C. Dickerson, is com- 

 pleted, and Avill be open to the public by the 

 end of March. Among those who have 

 worked on the group are Mr. Frederic H. 

 Stoll, colorist and wax modeler, Mr. Hobart 



The late Dr. Henry M. Liipziger, 

 supervisor of the Board of Public 

 Lectures, New York City 



Xichols, landscape artist, and the late Mr. 

 Ernest W. Smith, taxidermist. 



The death, at the close of 1917, of Dr. 

 Henry M. Leipziger, supervisor of the Board 

 of Public Lectures of New York City, was 

 an event of large importance inasmuch as it 

 deprived this city of a man whose concern 

 for the education of the masses has been one 

 of the great uplifting influences in the com- 

 munity. Dr. Leipziger was a native of 

 Manchester, England. He came to America 

 in his youth and obtained 

 ids education in the pub- 

 lit; schools and colleges of 

 New York City, in which 

 he afterward gave in- 

 struction for eight years. 

 Til health compelled him 

 to give up this work, 

 whereupon he traveled 

 iind studied in Europe 

 for three years. When 

 lie returned to New York, 

 in 1883, the city was en- 

 deavoring to deal with the 

 problem of adjusting 

 itself to the needs of a 

 large influx of Jewish im- 

 migrants, and he was 

 asked to take charge of a 

 trade school for boys. 

 Later, he organized the 

 Hebrew Technical Insti- 

 tute. Dr. Leipziger com- 

 bined the qualities of the 

 student and thinker with 

 wide human sympathies. 

 It became the dream of his life to bring 

 the privileges of higher education within 

 reach of all the people. To this end he 

 devised and introduced into the schools the 

 public lecture system, which from a small 

 beginning has developed into a number of 

 elaborate courses, each comprising a series 

 of lectures upon topics of general interest 

 in science, literature, music, and art. The 

 American Museum has been one of the cen- 

 ters for these lectures for many years. It 

 is hoped that this great work for the people, 

 to which he devoted his entire energies for 

 more than twenty years, will not be allowed 

 to disappear from the public educational 

 system of New York. 



A BULLETIN entitled "A War Time Diet," 

 issued in February by the department of 



