576 



THE POPULAR SCIENCE MONTHLY. 



on the plate, from the position of which,- 

 taken in conjunction with that of the sun, 

 the oscillations of the axis and point of the 

 projectile could be calculated. The results 

 obtained showed that both perform oscilla- 

 tory movements during flight very different 

 from those usually believed to take place. 



Two Akka girls, representing the dwarf 

 race of Africa on exhibition in the European 

 cities and supposed to be between seventeen 

 and twenty years old, are described as being 

 well proportioned, and as tall as a boy eight 

 years of age. Their behavior is infantile, 

 wild, and shy, but without timidity. They are 

 very different in disposition ; the more pleas- 

 ant one laughs joyously, is pleased with 

 bead bracelets and other trinkets given to 

 her, and curiously expressed her appreciation 

 of some chocolate bonbons. They show no 

 wonder or admiration at persons and things, 

 and are not affected by artistic furnishings, 

 and their eyes are without expression. 



A correspondent of Nature tells of some 

 letters and papers on his desk which were set 

 on fire by a paper weight composed of four 

 glass balls. It concentrated the rays of the 

 sun upon them. The desk was scorched, and 

 the burning papers, falling upon the carpet, 

 burned that. 



Two instances of what may be called 

 " dust photographs " are described in Nature 

 by W. B. Croft, of Winchester College. The 

 plate-glass window of a hotel in London has 

 on the inside a screen of ground glass, near 

 but not touching, on which are the words 

 " Coffee Room " in clear, unfrosted letters. 

 One day, as Dr. Earle, the writer's informant, 

 was at breakfast, the screen was taken away, 

 but the words were left plainly visible on the 

 window, and no washing would remove them. 

 In another case the house had been a hotel, 

 and the windows had been dressed with brown 

 gauze blinds, bearing the words "Coffee 

 Room " in gilt letters. A succeeding tenant 

 on misty days saw these words on one of the 

 windows. 



The results of six months' observations 

 of Mars have led Mr. Schacherle, of the Lick 

 Observatory, to the conclusion — contrary to 

 the generally received view — that the dark 

 portions of the disk represent land, and the 

 light portions water. This is supported by 

 observations of San Francisco Bay from Mount 

 Hamilton, in which the bay appears brighter 

 than the neighboring valley and mountains 

 at the same distance. On this hypothesis the 

 " canals " would correspond to ridges of moun- 

 tains almost wholly immersed in water, while 

 their doubling may represent parallel ridges 

 of which our own earth furnishes examples. 



The dangers of poisoning in the manu- 

 facture of white lead are avoided in a process 

 introduced by Mr. J. B. Hannay, by which a 

 sulphate of lead is produced instead of a car- 

 bonate. The pigment is made direct from 



the cheapest lead ore, which is crushed and 

 fed into coke furnaces. The heat combined 

 with an air-blast causes the lead to volatilize ; 

 the fumes are exposed to a current of steam, 

 and the resultant creamy- white liquid mass 

 is run off into settling tanks, whence it is 

 passed into filter presses, deprived of its 

 moisture, and dried and packed for market. 



Some oysters experimented upon by Prof. 

 R. C. Schiedt, under exposure, living, to light 

 with the right valve of the shell removed, in 

 the course of a fortnight developed pigment 

 over the whole of the epidermis of the ex- 

 posed right mantle and on the upper exposed 

 sides of the gills, so that they became dark- 

 brown all over that side. They also made a 

 partly successful effort to restore the right 

 valve. The inference is drawn from the 

 facts that the development of pigment in the 

 mantle and gills was wholly and directly due 

 to the abnormal and general stimulus of light 

 over their exposed surface, and that the man- 

 tle border, the only pigmented portion of the 

 animal, is pigmented because it is the only 

 portion which is normally and constantly sub- 

 jected to the stimulus of light. 



Attention has been called by Sir Henry 

 Mance to the damage inflicted on electric 

 telegraph cables by the teredo, which are de- 

 scribed as being really serious, and the sug- 

 gestion made by Mr. Preece several years ago 

 is approved by the author, that, besides sur- 

 veying the bottom of the sea for rocks and 

 shoals, the parts near the shore should be 

 examined to find whether they are infested 

 by this pest. 



In a paper published in Science, on Varia- 

 bility of Specific Characters in the Extinct 

 Genus Coryphodon, M. Charles Earle shows 

 that it is exceedingly difficult in this group 

 to find where one species ends and another 

 begins. In most cases the characters run 

 into each other insensibly. The author be- 

 lieves that there are about eight good 

 species, the characters of which show a 

 progression from the primitive to the more 

 specialized types. A later study by Mr. 

 Earle is on the comparative osteology of the 

 Malayan and the Brazilian tapirs. 



During a residence in Tunisia, M. Ver- 

 coutre made a study of the tattoo marks with 

 which the natives cover their limbs and face. 

 He discovered that the most complete de- 

 signs represent a human figure — a kind of 

 doll, seen in front, with extended arms. In 

 this figure, for which no explanation had 

 been offered before, he perceives nothing 

 else than a representation, rigidly exact and 

 preserved by tradition without perceptible 

 alteration, of the manikin on the monuments 

 of Phoenicia and Carthage, which archaeolo- 

 gists have named the " Symbol of the Punic 

 Trinity " — which is found, for example, on 

 the Phoenician and Punic stelae, and on the 

 neo-Punic lamps of Carthage. 



