November 30, 1883.] 



SCIENCE. 



707 



tliis had cooled, it was wrapped witli insulation- 

 tape, and served tightly with twine. This was 

 again covered with gulloot, then tape, and 

 tinally with melted gutta-percha ; and, when the 

 gntta-i)ercha had cooled, its entire surface was 

 scared over with a hot iron to ma^e sure of 

 tilling any cracks or holes it might contain. 

 The lami) was then lowered into the sea, about 

 seven hundred and fifty feet of cable being paid 

 out, without any indication of failure. To as- 

 certain if the lamp was lighted at all times, we 

 substituted a lamp for the cut-out plug in the 

 deep-sea circuit. This brought both lamps in 

 the same circuit, which caused them to glow 

 at about a cherry-red instead of a white light ; 

 and had any accident happened to break the 

 lamp in the water, or to cause a le.ak, our upper 

 lamp would have immediatelv sprung into in- 

 candescent whiteness. G. W. Baird, 



Passed assistant engineer, U.S.N. 



-COMMISSION STKAMBR ALBATKOSS. 

 KD ELECTRIC LIUUT TO ATTRACT FIB 

 ir.I.t:MINATK TIIK WATER. 



CRYSTALS IN THE BARK OF TREES. 



In examining the interior of certain insects 

 and myriapods living in and feeding on the 

 wood and liber of decaying trees, the writer 

 has often had his attention attracted b}- many 

 lieautiful and well-defined crystals mingled with 

 t he food-contents of the intestinal canal. The 

 I rystals appear to be insoluble in the intesti- 

 nal juices, as they pass through the entire 

 iract unchanged. Eecently, in examining a 

 large lamellicorn larva obtained from beneath 

 I he bark of a decaying white oak, I .again ob- 

 --erved an abundance of the same kind of cr3-s- 

 lals; and shortly after, numerous others were 

 lound in a Pol\ desmus taken from beneath the 

 bark of a hickorj- log. Feeling sufficient in- 

 terest in the matter to learn the source of the 

 crystals, I examined a large white oak, dead 

 and decaying, but still standing, with the bark 

 looselj- attached. On the inner side of the 

 b.ark was a thick, yellowish-white, pulverulent 

 layer, — the dec.a3'ed liber. This readily crum- 

 bled to powder; and a small portion, diffused 

 in water and submitted to the microscope, ex- 

 hibited a multitude of crystals, forming the 

 greater proportion of the powder, and of the 

 kind previously noticed in insects. The crj-s- 

 tals appeared perfectly fresh, and not changed 

 • by the surrounding decaj-, but were isolated, 

 sharply' defined, and highly lustrous. The3' 

 measured from about the two-thousandth to the 

 six-hundredth of an inch. Two forms were 

 common, — simple, as represented in fig. 1; 

 and twinned, as in fig. 2. A portion of the 

 powder was submitted to my friend, Prof. F. 

 A. Genth, for analysis, without informing him 



