FARMERS' REGISTER— ANALYSIS OF MULBERRY LEAVES. 



755 



shaped raft, Avhich will float, of egjTs heavy 

 enough to sink in water if dropped into it one by 

 one. The eggs are nearly of tiie jjyraniidal form 

 of a pocket gunpowder-flask, rather pointed at the 

 under end, with a projection like the mouth of a 

 bottle. Tiie first operation of the mother gnat is 

 to fix herself by the four-legs to the side of a 

 bucket, or upon a floating leaf, with her body 

 level with and resting upon the surfiice of the 

 water, excepling the last ring of the tail, wlrich 

 is a little raised; she then crosses her two hind 

 legs in Ibrm of an X, the inner opening of which 

 is intended to form the scaffolding of her structure. 

 She accordingly brings the inner angle of her 

 cros.sed legs close to the raised part of her body 

 and places in it an egg, covered, as is usual among 

 insects, with a glutinous fluid. On each side of 

 this egg she places another, all which adhere firm- 

 ly together by means of their glue, and form a 

 triangular figure thus ** , which is the stern of 

 the raft. She proceeds in the same manner to add 

 egg after egg in a vertical (not a horizontal) po- 

 sition, carefully regulating the shape by her cross- 

 ed legs; and as her raft increases in magnitude, 

 she pushes the whole gradually to a greater dis- 

 tance, and when she has about half-finished, she 

 uncrosses her legs and places them parallel, the 

 angle being no longer necessary lor shaping the 

 boat. Each raft consists of from two hundred 

 and fifty to three hundred and fifty eggs, which, 

 when all laid, float on the water secure trom sink- 

 ing, and are finally abandoned by the mother. 

 They are hatched in a lew days, the grubs issuing 

 from the lower end; but the boat, now composed 

 of the empty shells, continues to fioat till it is de- 

 stroyed by the weather.* 



Kirby justly describes this little vessel as resem- 

 bling a London wherry, being sharp and higher, 

 as sailors say, fore and aft, convex below and con- 

 cave above, and always floating on its keel. "The 

 most v^olent agitation of the water," he adds, 

 "cannot sink it, and what is more extraordinary, 

 and a property still a desideratum in our life-boats, 

 though hollow, it never becomes filled with water, 

 even though exposed. To pat this to the test, I 

 placed half a dozen of these boats upon the sur- 

 face of a tumbler half-full of water: I then poured 

 upon them a stream of that element from the 

 mouth of a quart bottle held a foot above them. 

 Yet after this treatment, which was so rough as 

 actually to project one out of the glass, I found 

 them floating as before upon their bottoms, and not 

 a drop of Avater within their cavity."! We have 

 repeatedly pushed them to the bottom of a glass 

 of water; but they always came up immediately 

 to the surfiice apparently unwetted. 



From the American Rail Road Journal. 



Avery's rotary engine. 



In our brief notice of this engine in the last 

 number of the Journal, we omitted to state a verj' 

 important fact in relation to the construction of its 

 boiler and chimney. 



It has been deemed a very important matter, 

 and great efforts have been made, to construct lo- 

 comotives in such a manner as to avoid the dan- 

 ger arising from sparks from the chimney — with 



* Reaumur, Mem. iv. p. 621. 

 t Introd. iii. p. 32. 



what success others have met, we cannot say; but 

 in this respect Mr. Averj- has been eminently suc- 

 cessful — as when we were with if, in running near 

 ten miles, not a particle of fire was discovered to 

 issue from the chinmey — and we are told that 

 neither fire nor cinders ever annoy passengers, as 

 they never come out of the chimney. 



From further experiments and investigation in 

 relation to this engine, we are disposed to /)re(/i'd 

 — although no pretensions are made to the gilt of 

 prophecy — that a locomotive engine will be con- 

 structed upon Avery's plan, within the next six 

 months, which shall make a trip fiom Jersey City 

 to Newark, and back again to the Ferry, in 45 

 minutes, with 100 passengers — passing the Bergen 

 Plill, with an elevation of 152 feet to tlie mile. 



ANALYSIS OF THE LEAVES OF THE MULBER- 

 RY. 



'I'ranslatcd for tlie Fanners' Register from the Sommaire des se- 

 ances dp. la Socicte Royale et Ccnlrale d'^gricutturc of Decem- 

 ber 1834. 



M. D'Arcet (the son) sends a letter upon a 

 chemical analysis which he has made of the 

 leaves of the mulherrj^ The result of this analy- 

 sis shows that the mulberry leaf contains four 

 parts in the 100 of azote. It may result from this 

 composition of mulberry leaves, that silk being a 

 product in a high degree supplied with azote, as 

 an ingredient, mulberry leaves for the nourishment 

 of silk worms could not be advantageously subi;ti- 

 tuted except by other leaves which also contain 

 azote. Then, as it is not knoAvn whether other 

 leaves contain as much azote, he will, to that end, 

 make the analysis of such other leaves as are con- 

 sidered proper substitutes for mulberry leaves. 



M. Chevreul says that the presence of azote 

 has long been known in the leaves of the mulber- 

 ry, and likewise in the leaves of many other 

 plants: that the diflerence which is said to exist 

 between animal and vegetable substances, rela- 

 tively to the presence of azote in the former, has 

 always been faulty — because, that it", in the mass, 

 there existed more azote, proportionally, in an ani- 

 mal than in a vegetable, still there were immedi- 

 ate products of animals which contained very little 

 azote, and even none — while there were immedi- 

 ate products of vegetables which contained nmch 

 azote — and vice versa. It is not then only the 

 analysis of the vegetables which is necessary, ac- 

 cording to M. Chevreul, but also the analysis of 

 their immediate products — and especially, to un- 

 derstand well what of the immediate products 

 serve for the nourishment of the silk worm — since 

 it is well known that insects, even more than other 

 animals, have the property of rejecting, among 

 the vegetable substances on which they feed, and 

 almost as they are taken, those parts which cannot 

 serve for their nourishment, and for the preparation 

 of the secretions which the insects yield. 



M. Ardouin adds, in support of what M. ("hev- 

 reul says, that there are many kinds of caterpillars 

 which produce sillc, and in as great quantity as the 

 silk worm, and which live on trees which cannot 

 furnish sujiport to the silk worm. 



M. Payen says that, according to his own ex- 

 perience, all the vegetables upon which experi- 

 ments have been made contain azote dans: iin 

 principe continu fi-om the extremities of the roota 

 to the extremities of the leaves — a.n(i even in tho 



