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THE POPULAR SCIENCE MONTHLY 



they now are." The different kinds of fish 

 now in these ponds are California salmon, 

 Kennebec salmon, brook-trout, salmon-trout, 

 grayling, a hybrid of California salmon and 

 brook-trout, also a hybrid between salmon- 

 trout and white-fish. 



Graves of the Monnd-Builders. On 



opening a sepulchral mound on Coup's 

 Creek, Macoupin County, Illinois, four skel- 

 etons were found sitting two-and-two, with 

 the arms crossed, and the knees of one 

 pair pressing sharply against the backs 

 of the other. The grave was six feet in 

 length by three in width, and search was 

 made for other remains. Nothing, how- 

 ever, was found, except four large marine- 

 shells, identified as of the Linnaean spe- 

 cies Busycon perversum. The position 

 of each of these shells in relation to 

 the skeletons was the same : the smaller 

 end of one had been placed in the right 

 hand of each, while the larger portion rest- 

 ed in the hollow above the left hip. But 

 what will appear most singular in this re- 

 markable find is the fact that each shell 

 contained what seemed to be the bones of 

 an infant. " Within each of the shells," 

 writes Mr. John Ford, in the " Proceedings" 

 of the Academy of Natural Sciences of Phil- 

 adelphia, "there had been packed what 

 appeared to be the bones of a child ; the 

 skull, which evidently had been crushed 

 before burial, protruding beyond the aper- 

 ture. Of course, any hypothesis regarding 

 the purpose of this peculiar rite must neces- 

 sarily be of a conjectural character ; never- 

 theless, it was difficult to resist the conclu- 

 sion that these infants were sacrificial offer- 

 ings to the spirits of the dead, whom the 

 living desired to honor." 



Non-Poisonous Coloring for Preserved 

 Vegetables. A patented process, for giving 

 to cooked and preserved vegetables a green 

 color, without the employment of copper or 

 any other poisonous substance, is described 

 as follows : First, the green leaves of some 

 such plant as spinach, or sorrel, are scald- 

 ed for a few minutes with boiling water, 

 and drained ; they are then triturated with 

 knives or other cutting instruments. Next 

 the triturated mass is heated with an equal 

 weight of caustic soda solution marking 

 12.5 Beaume, the mixture being boiled till 



the leaves are dissolved. From the product 

 prepare a "lacker" by precipitating alum 

 with this alkaline solution of chlorophyl, 

 and then draw off* and wash the precipitate 

 in abundance of water, and finally press out 

 the excess of water. To prepare the lacker 

 for use, about thirty pounds of it is put in a 

 basin with about fifteen pounds of soluble 

 phosphates, especially phosphates of soda, 

 potash, or ammonia, or of acid phosphates, 

 or alkaline citrates, or double tartrates, and 

 water is added until the liquor marks 2 

 to 5 Beaume. To communicate the green 

 color of this chlorophyl preparation to 

 cooked or preserved vegetables, the latter 

 have only to be immersed for a few min- 

 utes in the solution at a temperature of 

 212 Fahr. The effect of the operation is 

 to impart to the products treated a fine, 

 permanent green color, due to the absorp- 

 tion and fixation of an excess of chloro- 

 phyl. 



Compressed Air in Coal-Mining. An 



English journal gives an account of certain 

 experiments recently made at Wigan to 

 show how compressed air may be substi- 

 tuted for fiery explosives in coal-mining. 

 A " cartridge," or reservoir, was placed in 

 a shot-hole, after the manner of a charge 

 of powder, and rammed or plugged in the 

 same way. This chamber is in connection 

 with a powerful air-pump, adapted express- 

 ly for the purpose, and, by simply turning a 

 wheel, the collier can " fire his shot " with- 

 out the least danger of setting fire to the 

 inflammable gases. Mr. Marsh's (the in- 

 ventor's) machine is capable of exerting a 

 pressure of over 12,000 pounds to the square 

 inch, and this forpe can be produced by two 

 men turning the wheel in less than three 

 minutes from the time of ramming the car- 

 tridge. The Wigan experiments show that 

 very large quantities of coal can be brought 

 down at a very much less expenditure of 

 force. The first cartridge " fired " was 

 burst at a pressure of 7,500 pounds to the 

 square inch, the pressure being registered 

 by a gauge. The coal was fractured, but 

 not brought dow r n ; and a second cartridge 

 was inserted, and burst at a pressure of 

 8,250 pounds to the square inch, completely 

 loosening the coal and breaking up about 

 eight tons. The whole force of the shot 

 was probably not exerted on the seam, as 



