7i6 



THE POPULAR SCIENCE MONTHLY. 



of the lot, they are by no means the only 

 ones containing arsenical pigments. A re- 

 cent number of the " Lancet " gives an ac- 

 count of an aggravated case of poisoning, 

 due to a red paper on the walls of a sitting- 

 room ; and arsenic has also been found in 

 white, gray, blue, mauve, and brown wall- 

 papers in abundance. As an instance of 

 the utter disregard of consequences shown 

 by manufacturers in the use of these pig- 

 ments, we may cite the statement published 

 by Miss Osborne, of the Sydney Hospital, 

 New South Wales, that large quantities of 

 poisonous pigments are consumed in that 

 colony in coloring sweetmeats for children. 

 We give in another place in this number a 

 letter from a chemist in Pittsburg, show- 

 ing an equally flagrant case of carelessness 

 in the manufacture and use of arsenical 

 papers for the operations of the kinder- 

 garten. People who thus disregard the 

 welfare of their fellows, scattering poison 

 broadcast in a way that neither age nor con- 

 dition can escape, are, we submit, entitled 

 to some small share of attention from the 

 press, and from the courts. 



irtificial Diamonds.— The " todo " about 

 the artificial production of the diamond has 

 been set at rest by Professor Maskelyne, 

 who, in reply to numerous letters of inquiry 

 on the subject, sends to " Nature " the re- 

 sults of his examination of the Macteor 

 specimens which came into his hands for 

 the purpose. lie tested these so-called dia- 

 monds — 1. With reference to their hard- 

 ness ; 2. Their refracting power ; and, 3. 

 Their combustibility. The samples sent to 

 him were " too light to possess appreciable 

 weight, too small even to see, unless by very 

 good eyesight or with a lens," yet were suf- 

 ficiently large to serve his purpose. "A 

 few grains of the dust — for such the sub- 

 stance must be termed — were placed between 

 a plate cf topaz — a cleavage-face with its 

 fine, natural polish — and a polished surface 

 of sapphire, and the two surfaces were care- 

 fully * worked ' over each other with a view 

 to the production of lines of abrasion from 

 the particles between them. There was no 

 abrasion. Ultimately the particles became 

 bruised into a powder, but without scratch- 

 ing even the topaz. They were not diamond. 

 Secondly, some particles more crystalline in 



appearance than the rest were mounted on 

 a glass microscope slide and examined in 

 the microscope with polarized light." They 

 each and all presented powerfully the prop- 

 erty of doubly refracting light. Finally, two 

 of these microscopic particles were exposed 

 to the intense heat of a table blowpipe on 

 a bit of platinum-foil. They did not burn. 

 They were afterward placed in contact witk 

 two little particles of diamond-dust, exceed, 

 ing them in size, and the experiment, on be. 

 ing repeated, " showed that the diamond 

 particles glowed and disappeared, while the 

 little particles from Glasgow were as obsti. 

 nate and as unacted on as before." When 

 subjected to a stream of oxygen gas the re- 

 sult was the same. Hence, Professor Mas- 

 kelyne concludes that the substance sup. 

 posed to be artificially formed diamond is 

 not diamond and is not carbon. Further ex- 

 periments led him to the conclusion that 

 it consisted of some crystallized silicate, or 

 possibly of more than one such. 



The fate of the Glasgow diamonds has 

 induced Professor W. Mattieu Williams to 

 send to " Nature " an account of his experi- 

 ence in diamond-making, for the benefit of 

 those who may have an attack of the diamond 

 mania. He states that for the popular 

 class-room experiment of burning phospho- 

 rus in oxygen he used a cup of chalk, deep- 

 er and with a smaller rim than the brass 

 cups usually made for this purpose — the 

 object of this being to check too rapid out- 

 burst of combustion. He observed that a 

 cup, several times used for this purpose, 

 became coated on the inside with a hard, 

 glassy enamel, which he supposed to be 

 phosphate of lime. To test this, the cup 

 was thrown into hydrochloric acid and dis- 

 solved, but at the bottom there remained 

 a residue of insoluble crystalline particles. 

 " Could it be possible that the carbonic 

 acid, driven off by heating the chalk, had, 

 in reaching the heated phosphorus, become 

 dissociated, its oxygen combining with the 

 phosphorus, and its carbon thrown down 

 as veritable diamond ? " These crystalline 

 particles when tested were found to scratch 

 a glass pestle and mortar in which they 

 were rubbed, but were too small for further 

 examination. To obtain a better supply, 

 phosphorus was dissolved in bisulphide of 



