252 



THE POPULAR SCIENCE MONTHLY. 



Builder calls enormous, and accordingly 

 christens the new stone " Queen of Dia- 

 monds." But the Builder is plainly in 

 error here, for there are many diamonds 

 which weigh far more. Thus, the Grand 

 Mogul is the owner of a rose-diamond 

 which, in the rough state, weighed 780-J- 

 carats. It lost very largely in the cutting, 

 weighing now only 136 carats. It is val- 

 ued at over two and a quarter millions of 

 dollars. A potentate in Borneo owns a dia- 

 mond weighing 367 carats. The " Regent " 

 weighed in the rough 410 carats. The " Or- 

 loff " weighs 19-tf, and may have weighed 

 thrice as much in the rough state. An Aus- 

 trian diamond weighs 139^, and, as the 

 lapidary cannot cut these stones without 

 depriving them of at least half their weight, 

 it must have been, in the rough, larger than 

 the Cape " Queen." But the name given to 

 this newly-found stone will appear still more 

 incongruous when we consider its quality. 

 A diamond is said to be of the first water 

 when it is perfectly limpid and colorless, 

 and free from flaws, and of the second or 

 third water in proportion as it departs from 

 this standard. But this Cape diamond is 

 of a yellow color, and marked with flaws 

 it is, therefore, not of the first water, and 

 would in all probability be classed by the 

 lapidary as of the third water. 



Production of Sea-Salt in Portngal. 



The salines of Portugal, at Setubal, Lisbon, 

 Aveiro, and Algarve, yield annually 250,000 

 tons of sea-salt. According to Prof. Wau- 

 klyn, in the Mechanics' Magazine, the pro- 

 cess of manufacture at the first-named place 

 is as follows : There is a vast reservoir of 

 about four acres in extent, eight inches deep, 

 and partitioned into squares of about 130 

 yards in surface. Roads, three feet wide, 

 separate the squares, and the latter all com- 

 municate with the main reservoir of sea- 

 water. In autumn the whole salt marsh is 

 overflowed to the depth of 20 inches. This 

 water evaporates in the spring, the roads 

 appearing above the surface in June. Then 

 the tanks are cleaned out, and afterward 

 left to themselves, and recharged from time 

 to time with new supplies of water. In 20 

 days a layer of salt over one inch thick is 

 found. This, the first crop, is collected, 

 and the tanks filled again. In 20 days an- 



other crop is gathered. If the season is 

 favorable, three crops may thus be col- 

 lected before September, when the marsh is 

 flooded for the winter. 



Controlling Sex in Butterflies. The 

 America?). Naturalist for March contains an 

 admirable essay by Mrs. Mary Treat, in 

 which she brings a long array of facts to 

 prove that the sex of butterflies depends, 

 in some cases at least, rather upon the ex- 

 ternal conditions surrounding the larva, or 

 caterpillar, than on its anatomical structure. 

 The results of the author's experiments con- 

 tradict the doctrine of most entomologists, 

 which asserts that even in the eggs of the 

 Lepidopiera the germs of sexual difference 

 may be discerned. The editor of the Natu- 

 ralist quotes from several authorities, to 

 show that, in the case of all animals which 

 reproduce by eggs, the sex is probably de- 

 termined at or about the time of concep- 

 tion, or at least early in the embryonic stage. 

 Mr. T. W. Wonfor also, writing on " Certain 

 Wingless Insects," in Harduiicke for March, 

 asserts that the very same conditions, viz., 

 lack of abundant food, or alternations of 

 scanty and bountiful food, which, according 

 to Mrs. Treat's experiments, determine the 

 sex of the future imago, or butterfly, tend 

 only to " produce dwarfs or monstrosities." 

 The writer in Harduiicke, we may add, holds 

 that no sex-difference is discernible either 

 in the eggs or in the lame. Mrs. Treat's 

 observations and experiments, it will be 

 seen, were very thoroughgoing and very 

 carefully conducted, and will, doubtless, at- 

 tract the earnest attention of naturalists. 

 Some two years ago Mrs. Treat placed a 

 larva, which had already taken some steps 

 toward the chrysalis state, upon a fresh stem 

 of caraway, and was surprised to see it 

 commence eating. It then continued to 

 eat for some days before changing to a 

 chrysalis. She next placed a number of 

 other larvae on similar stems of caraway, 

 while still others she deprived of food alto- 

 gether. Those of the last lot which com- 

 pleted their transformations were all males, 

 and all the butterflies from the first lot were 

 females. 



The next experiment was commenced in 

 June last. In July the author had about 

 two hundred larvae feeding at once. Im- 



