912 Teansactioxs of the American Ikstitute. 



4 



face. Strangely enongh, elie liolds the two hroad, liaiid-like extre- 

 mities of the arms against her body, and it is the inside of these arms 

 that secrete tlie paper-like shell, which is only a sort of cradle for her 

 eggs. Not so witli tlie pearly nantilns, which is furnished with a 

 beautiful coiled-up, pearly shell, foi-med on the outside of the animal. 

 The shell is divided into numerous chambers, and the animal, living 

 in the outer one, builds a partition across the back part of it as the 

 shell grows. Cuttle-fish are sometimes used for food by the Brazili- 

 ans, and different species may l)e seen in the markets, where one fre- 

 quently finds them still ajive. Sometimes as we stoop to examine 

 one, its body is suddenly suffused Avitli a deep pinkish glow. Before 

 we have time to recover our surprise this color fades, and a beautiful 

 blue takes its place as rapidly as a blush sometimes suffuses a deli- 

 cate cheek. The blue, perliaps, is succeeded by a green, and then 

 the whole body becomes pink again. One can hardh^ conceive any- 

 thing more beautiful than this rapid play of colors, which is pro- 

 duced by the successive distention of sets of little sacks containing 

 fluids of different colors wliich are situated under the skin. The cut- 

 tle-fish is also furnished with a bag containing an inky fluid, which, 

 when the animal is attacked or pursued, it ejects into the water, thus 

 completely blinding its adversary and effectually covering its retreat. 

 It is from this fluid that the color sepia is made. Beside carrying an 

 ink bottle, some species of cuttle-fish are provided with a long, deli- 

 cate, horny pen, which forms a sort of stiffener to the back. In some 

 species the pen is hard, thick and broad, and the cuttle-fish bone of 

 commerce is of this kind. The species found in our waters is very 

 small, and not at all dangerous, being barely large enough to draw 

 blood from the hand ; but in the tropical seas thej are very large, 

 powerful, and dangerous. The cuttle-fish is the original of Victor 

 Hugo's devil-fish, so vividly described in tlie " Toilers of the Sea." 

 If the devil-fish were a beneficent one, Mr. Ilartt says he should be 

 sorry to destroy our faith in it ; l)ut as it is, he believes it will be 

 rather a relief than otherwise to know that in some important res]K'cts 

 Victor Hugo's story of it is a fable. The kraken was a mythical 

 cuttle-fish of fabulous size. 



Ascertaining the Duty of Steam Engines. 

 # W. Ashton and J. II. Storey. — A comparatively small cylinder is 

 fitted with a piston, and is connected with the cylinder of the steam 

 engine in such a manner as to allow tlie piston to be acted upon by 



