POPULAR MISCELLANY. 



6Sy 



32, and 39. In the same districts the num- 

 ber of persons to a square mile is IGO, 1S6, 

 379, 1,718, 4,499, 12,351, and 63,823. Thus, 

 ia Liverpoo], the densest and the unhealth- 

 iest district in England, there were 63,823 

 to an acre ; of whom 39 per 1,000 died an- 

 nually. This series of facts may be put in 

 a different way ; The nearer people live to 

 each other the shorter their lives are. Thus 

 the proximity of people in 53 districts is 147 

 yards, the mean duration of life is 51 years; 

 in 345 districts the proximity is 139 yards, 

 and the mean duration of life is 45 years ; in 

 137 districts the proximity is 97 yards, and 

 the mean duration of life is 40 years ; in 47 

 districts the proximity is 46 yards, and the 

 mean duration of life is 35 years ; in 9 dis- 

 tricts the proximity is 28 yards, the mean 

 duration of life is 32 years. In Manchester 

 district the proximity is 17 yards, and the 

 mean duration of life is 29 years ; in Liver- 

 pool district the proximity is 7 yards, and 

 the mean duration of life is 26 years. This 

 Ls a determined law, and, the duration of life 

 being given in one set of conditions, the 

 duration of life in another set of conditions 

 is determined from the proximities. 



An Interesting Collection of Sonth Ameri- 

 can Fossils. — Prof. Cope bought the collec- 

 tion of fossil bones from the Argentine Con- 

 federation which were brought to show at 

 the Paris Exposition. Sevei'al countries are 

 said to have wanted them. They will be of 

 value in this country, because the chief por- 

 tion of them are not to be found anywhere 

 in the United States. They come from Pat- 

 agonia, and the collection includes about 

 one hundred and fifty specimens of animals. 

 There are nineteen skeletons, chiefly of large 

 animals, almost completely whole, among 

 which are armadilloes and sloths. One of 

 the armadilloes has a curious tail which in- 

 creases in size toward the end, at which 

 point it takes an oval shape and is from a 

 foot to eighteen inches wide. Unlike that 

 of all other armadilloes, it is without joints, 

 except that at the base. It is supposed to 

 have been a fighting weapon. Another rare 

 specimen is a sabre-toothed tiger, of which 

 there is only one other known specimen in 

 the world. The size of the sloth skeletons 

 varies from that of a small black bear to the 

 largest elephant. The sabre-toothed tiger 



and the club-tailed armadillo are supposed to 

 have been monarchs of the forests in their 

 day. It has not yet been determined to 

 what institution of science the collection is 

 to be presented. 



Artificial Diamonds. — In examining the 

 papers of their deceased father, J. N. Gau- 

 nal, Messrs. A. and F. Gaunal found one 

 which purported to be a copy of a memoir 

 presented by him to the Paris Academy of 

 Sciences in 1828, and which gave an ac- 

 count of a process for the artificial produc- 

 tion of diamonds. The Academy simply 

 buried the communication in its archives, 

 and never mentioned it in any way. The 

 substance of this document is now published 

 in " Le Monde de Science et de I'Industrie," 

 from which we take the following particu- 

 lars : Equal weights of carbon sulphide and 

 of phosphorus, both as pure as possible, 

 are put in a flask, and a little water added 

 which floats on the top and prevents the 

 sulphide from turning to vapor and from 

 taking fire. The whole having been placed 

 in some situation where it will not be dis- 

 turbed, the sulphur of the sulphides com- 

 bines with the phosphorus and releases the 

 carbon, which falls to the bottom and as- 

 sumes a^crystalline form. This result takes 

 place slowly, and not till after the lapse of 

 six months was M. Gaunal able to obtain 

 diamonds the size of a grain of millet-seed. 

 As for the purity of these small diamonds 

 it was proved by the strictest tests, and 

 that not only by M. Gaunal but also by 

 others. The experiment was repeated sev- 

 eral times in the course of many years by 

 M. Gaunal, and always with the same re- 

 sult. The artificial diamonds consist of 

 pure carbon in dodecahedral crystals, and 

 they scratch steel like the natural diamond. 



Protection of Iron Surfaces from Rnst. 



— We have already briefly described Pro- 

 fessor Barfly's method of rendering the sur- 

 face of iron unoxidizable, yet, by way of in- 

 troducing some remarks on the results of 

 the process published in the " Lancet," we 

 may repeat that it consists merely in sub- 

 jecting the iron to the action of superheat- 

 ed steam — steam having a temperature of 

 1500° Fahr. This steam is generated in an 

 I upright boiler, and is then conducted through 



