It was during my first visit to Brazil, that one day, whilebusily engaged in examining a reef at a little town on thecoast call ed G uarapary, my eye fell on an Object in a shallow tide-pool, packed away in the crevice of the reefwhich exicited my curiosity. I could see nothing but a pair of very bright eyes ; but, concluding that the eyes had an owner, I deter mined very rashly to secure ;him. I had been handling corals and seemed to have fOTgottll! that all the inhabitants of the sea were not harmless. I put my hand down very quietly so as not to rume the water. When, suddenly, to my surpj'ise, it was seized with a pressure far too ardent to be aareeable andI was held fast. I tugged hard to get a way, bu ? this u?civilindividual , whoever he waR, evidently had as strong a hold onthe rocks as he had on my hand, and was not easily to 'be persuaded to let go of either. At last, however, he became convinced that he must choose between ue, and so let go his hold about my left hand also, and I was a helpless prisoner In vain I struggled . ,to free myselfhe only clasped me the tighter. In vain I shouted to my companionhe had wandered out of hearing. I was momentarily expecting to be bitten, wheri the “ bicho” suddenly changed his mind. I was never able to discover whether he was smitten with remark and retired with amiable intentions, or whether he only yielded to the force of circumstances. At any rate he suddenly relinquished his hold upon my h ands and dropped to the sand. Then raising himself on his long limsy arms, he stalked away towards the water, making such a comical figure, that in spite 0f my fright I indulged in a hearty laugh. He looked like a huge and a very tipsy spider, staggering away on his exceedingly long legs. It was during my first visit to Brazil, that one day, while busily engaged in examining a reef at a little town on the coast called Guarapary, my eye fell on an object in a shallow tide-pool, packed away in the crevice of the reef, which ex'Cited my curiosity. I could see nothing but a pair of very bright eyes; but, concluding that the eyes had an owner, I determined very rashly to secure ;him. I had been handling corals and seemed to have forgottll! that all the inhabitants of the sea were not harmless. I put my hand down very quietly so as not to ruffle the water, when, suddenly, to my surprise, it was seized with a pressure far too ardent to be agreeable, and I was held fast. I tugged hard to get away, but this uncivil individual, whoever he was, evidently had as strong a hold on the rocks as he had on my hand, and was not easily t® be persuaded to let go of either. At last, however, he became convinced that he must choose between us, and so let go his hold The Cuttle fish belongs to the Mollusks, a branch of the animal kingdom distinguished for its members being built on the plan of a fac, and to which Mr. Hyatt has applied the more appropriate name of Saccata. The cuttle fishes are distinguished from all the other Mollusks, such as snails, clams, etc., by having a large head, a pair of large eyes, and a mouth furnished with a pair of jaws, around which are arranged in a circle, eight or ten arm s furnished with suckers. In the common cuttle fish Or squid of our coast, the body, which is long and narrow, is wrapped in a muscular eloak or mantel, like a bag fitting tightly to the back but loose in front. It is closed up to the necl\:, where it is open like a loosely-fitting overcoat buttoned up to the throat. Attached to its throat, by the middle, is a short tube open at both ends. This tube, or siphon as it is called, is fastened to its throat, and can be moved about in any direction. The animal breathes by means of gills, which are attached to the front of the body inside the cloak and look like the ruf- fies of a shirt bosom. By means of these gills the air contained in the water is breathed, and they answer the same purpose for the cuttle fish that our lungs do f>>r us. In order to swim, the animal swells out the cloak ill fromt so that the water flows in between it and tlil.e body. Then it closes the cloak tightly about the neck so that the only way the water can get out is through the siphon. Then it contracts very forcibly its coat, which, it must he remembered, is a part of the animal, and the water is driven out in a jet from the siphon under the throat, and the body is propelled in flie. opposite direction ; that is, backward like a rocket through the water. This siphon is flexible like a water hose, and can be bent so as to direct the stream not only forward, but sidewise and backward, so that the animal can move in almost any direction, or turn somersets with perfect ease, and so rapidly do some cuttle fishes swim that they are able to make long leaps out of the water. Unsually, however, the animal swims backward, with its long arms trailing behind. Our common cuttle fish of this coast has, in addition to its eight arms, two long slender tentacles which may be withdrawn into the body. 'I'he tail is pointed and furnished with a fin on each Mde. The Octopods. to which the Brazilian cuttle fish belongs, have round purse-like bodies, and eight arms united at the base with a web, and they swim by opening and shutting their arms like an umbrella ; in this mo.1e of swimming they resemble the jelly fishes. The paper Nautilus is nothing in the world but a female cuttle fish that builds a shell. There was a very pretty story told of her habits, by Aristotl*, the old Greek naturalist, which every one believ'” until quite recently. He said that she rode on the top of the waves, seated in her boat-like shell, and - spread her broad arms to the winds for sails. But unfortunately the story has no foundation in fact. She either crawls about on the bottom of the sea, or swims quite like any other cuttle fish, shell foremost, only occasionally coming to the surface. Strangely enough she holds the two broad hand-like extremi. ties of the arms against her body, and it is the inside of these arms that secrete the paper-like shell, which is onl^ a sort of cradle for her eggs. Not so with the pearly Nautilus, which is furnished with a beautiful, coiled up, pearly shell, formed on the outside of the animal. This 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 shel l grows. Cuttle fishes are sometimes used for food by the Brazilians and different species may be seen in the markets, where one frequently finds them still alive. Sometimes, as he stoops to examine one, its body is frequently suffused with a deep pinkish glow. Before he has time to recover from his surprise this color fades, and a beautiful blue takes its place as rapidly as a blush some times suffuses a delicate cheek. The blue, perhaps, is succeeded by a green, and then the whole body becomes pink again. One can hardly conceive anything more beautiful than this rapid play of colors, which is produced by the successive distention of sets of little sacks containing fluids of different colors, which are situated under the skin. The cuttle 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. Besides carrying an ink- bottle, some species of cuttle fish are provided with a long, delicate, horny pen, which forms a sort of stiffener to the back. In some species the pen is harq., thick, and broad, and the cuttle fish bone of comm erce is a pen 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 they are very large, powerful, and dangerous. The cuttle fish is the original of' Victor Hugo's devil-fish, so vividly described in the “ Toilers of the Sea.” If the devil fil3h were a beneficent creation, I should be sorry to destroy your faith in it ; but as it is, I believe it will be rather a relief than otherwise to know that in some important re- .speets, Victor Hugo's story of it is a fable. The Kraken was a mythical cuttle fish of fabulous size.American Naturalist. Boiler Explosioiis.---AntI-incrustation Compositions. At the Manchester (England) Steam Users' Association meeting, held recently, Mr. L. E. Fletcher, chief engineer, referring to one explosion, said the owner of the boiler had adopted a new composition for the prevention of incrustation for six or seven months before the explosion, This composition proved most efficacious for preventing incrustation. It removed the hard cakes adhering to the plates and reduced them to powder ; so that when the men entered the boilers for cleaning, instead of finding them coated as before with a tenacious scale requiring hammer and chisel to remove, they founi!, several bucketsful of flour or dust, which was readily washed, out. There must evidently have been a large quantity of this fine floury deposit accumulated in the boilers, and floating about in the water when they were at work The fine floury deposit appears to interfere with that intimate contact between the water and the plates which is necessary to pr«- © 1869 SCIENTIFIC AMERICAN, INC. 214 [OCTOBER 2, 1869. vent over-heating, while it may be that, from the thickened ! could be arrived at was, that the current °f riixtriclty m the watl'r, the globules of steam cannot freely escape, and, thus j instant of its passage, carried the outline of the figure of the cage.d' Wlihm it, linger longer in contact with the plates over j rabin down upon the body of the sheep, the sheep having the fire than Jh'ey should do, and thus form a film between fallen (if it were not already lying) upon its side, before the the iron and Hie water, in consequence of which the heat is j body of the robin reached it in its downward descent. No not carried 0ff rapidly enough and over-heating ensues. It is f doubt the sheep was lying down at the time °f the stroke. not intended by this that they are made red hot, but that they j Now whether the body of the robin absorbed a portion of the are heated sufficiently to so increase their ductility as to lead to the undue compression and the consequent deflection of the over-heated parts. The explosion is, therefore, attributed to over-heating of the iurnace crowns, though when covered with an ample supply of water, consequent on the accumulation within the boiler of a large amount of fine floury deposit, caused by the use of an arsenical composition for preventing m- crustation, coupled with the suicidal practice of neglecting to open the blow-out taps. This is the first explosion which has eyer occurred to a boiler guaranteed by this association ; and it will be impossible, without the hearty cooperation of the members, to prevent such, without imposing restrictions up°n them with regard to the treatment of their boilers, which the association has at all times been desirous to avoid. But this opportunity may be taken of strongly urging upon the members the advice which has repeatedly been given personally on previous occasionsthat they should not experiment cm their boilers with anti-incrustation compositions. They -will find i t a safe, and, in the majority of instances, a very efficacious plan to feed the boilers with two or three pounds of good soda ash daily ; the soda pot being introduced in heavy charges through the man-hole at cleansing times, but along with the feed, so that the boilers may be constantly fed with weak soda water ; while the blow-out taps, both at the bottom of the boiler and surface of the water, should be regularly used. There is a composition now strongly advocated which acts rather mechanically than chemically, by forming a thin film of varnish upon the plates, and thus preventing the adherence of the scale. With some waters this has its dangers; the fllm or coat of varnish may protect the plate from the water as well as from the incrustation, and thus lead to overhearing, and two cases of injury have lately beon met with which have arisen from this cause.