August 22, i8go.] 



SCIENCE. 



105 



this constitutes a decided economy, added to great facility, in ex- 

 traction and utilization . The structure of the plant permits of the 

 operations of separating and removing the bark being performed 

 by machinery, while in the other fibrous plants these operations 

 must be effected by hand, a system at the same time very costly, 

 and only possible in countries where there is a large number of 

 hands available and cheap. It is stated by the American special- 

 ist that he could construct a machine, costing no more than the 

 ordinary machines used for cotton, and which could be used in 

 the same manner. By this machine the fibre could be extracted 

 and sold by the pound in the same way as cotton. Persons cul- 

 tivating this plant would benefit in addition by the sale of the 

 fruit, which is much esteemed in the temperate and tropical 

 countries of the South, where the guimbobo grows luxuriantly, 

 and almost without any care. The fibre of the guimbobo has a 

 lustre similar to that of silk, and is undoubtedly finer and stronger, 

 with a creamy color between white and straw color. 



— A new gun, the invention of M. Giflfard, the well-known 

 French inventor, is attracting considerable attention among mili- 

 tary men in Europe. As described in the London Times, the pro- 

 pulsive agent in this novel weapon is carbonic acid gas, com- 

 pressed to a liquid condition, and capable of giving a pressure of 

 five hundred pounds per square inch. The liquefied gas is con- 

 tained in a metallic tubular reservoir about nine inches long, 

 which is fixed under and in a line with the barrel of the gun, and 

 which is conveniently grasped by the left hand in firing. Al- 

 though containing an immense store of power, there does not ap- 

 pear to be any danger in a weapon thus equipped. In the first 

 place, the reservoir is made of Siemens-Martin steel of the highest 

 quality, so that a burst is considered hardly possible; and, in the 

 second, should a flaw in the metal lead to a fracture, the gas 

 would simply escape much in the same way that it does on the 

 opening of a bottle of soda water. Then, the quality of the metal 

 used for the gas receiver is such that it will stand rough usage 

 without liability to fracture. It may be, and, indeed, has been, 

 knocked greatly out of shape when full of gas without any preju- 

 dicial result arising, the gas having been afterwards used for dis- 

 charging projectiles from the gun. The bullet is dropped into a 

 small aperture at the rear end of the barrel, and by moving a 

 small lever it is deposited in the breech chamber of the gun. The 

 hammer is then placed at full cock and the trigger pulled. By 

 the fall of the hammer a pin is struck which opens a valve at the 

 rear of the liquefied gas reservoir, and permits the instantaneous es- 

 cape of a sufficient volume of gas for one discharge. The bullet 

 is thus ejected with a force proportionate to the impelling power 

 of the charge, which can be increased or decreased at pleasure by 

 a simple screw arrangement. In other words, the propelling 

 power is completely under control, although, of course, this in 

 practice is not left to the arbitrary will of the ordinary user, but 

 will be fixed and definite, according to the character of the gun in 

 which it is employed. The discharge of the gun is unaccompa- 

 nied by any report, nor is there the least recoil or kick. On pull- 

 ing the trigger there is a slight hiss or puff, followed by the noise 

 of the impact of the bullet upon the iron target. The reservoir is 

 very light, and when charged with liquefied carbonic acid gas, is 

 capable, according to the size and calibre of the gun, of discharg- 

 ing from one hundred to five hundred consecutive shots at a stated 

 cost of less than one penny. It is stated that there is no fear of 

 any part of the gun or its mechanism becoming oxidized by the 

 gas, and it is hardly necessary to add that there is neither smoke 

 nor smell from the propellant. There is also no deterioration of 

 the liquefied gas from storage or keeping. With regard to the 

 rifle itself, with the exception of the tubular reservoir carried under 

 the barrel, there is no material difference in appearance between 

 the Giifard gun and an ordinary weapon of similar character. 



— The success which has attended the use of arsenical sprays 

 in combating the curculio upon the cherry and plum has led to 

 its trial upon peach trees. London purple appears to have been 

 most generally used in these trials, because this material has been 

 strongly recommended during the last few years as preferable to 

 Paris green. The advantages which London purple possesses over 

 Paris green are its cheapness, and the fineness and lightness of the 



material, allowing it to remain longer in suspension in water. 

 But the use of London purple upon the peach has often resulted 

 in great injury to the foliage, and .sometimes to the young shoots. 

 The injuries in the Michigan peach orchards last year led Pro- 

 fessor Cook, of the Michigan Agricultural Experiment Station, to 

 experiment upon the influence of the arsenites upon foliage. He 

 found that peach foliage is especially susceptible to injury, that 

 London purple is more injurious to foliage than is Paris green, and 

 that this is doubtless owing to the soluble arsenic which is quite 

 abundant in London purple and almost absent in Paris green. 

 The colored liquid left after the complete settling of the London 

 purple was destructive to peach foliage. It appeared that greater 

 injury occurred when the spraying was performed shortly before 

 a rain, and that spraying soon after the foliage puts out is less 

 harmful than when it is delayed a few days, or a few weeks. As 

 a general result of the trials upon the peach, it was concluded that 

 Paris green alone should be used, and that not stronger than one 

 pound to three hundred gallons of water. Experiments in the 

 same direction were performed at the Agricultural Experiment 

 Station at Cornell University last year and this year, and the 

 experiences of the two seasons coincide, so far as the experiments 

 are comparable. The trials at Cornell, as given in the July Bulle- 

 tin, show that peach foliage is very susceptible to arsenical poisons, 

 and that London purple is much more injurious than Paris green. 

 The young leaves are much less liable to injury than the full 

 grown leaves. This is supposed to be due entirely to the waxy- 

 covering which is so abundant upon recent leaves and shoots. 

 Late in the season, when the young and waxy growth is slight, 

 nearly all the leaves will be killed by a mixture which would have 

 had scarcely any effect when the tree is just pushing into growth 

 in spring. Injury early in the season is less apparent, also, 

 for the reason that growth of new leaves is so rapid that defolia- 

 tion is obscured. In fact, the casual observer would not have 

 noticed that the trees which shed their leaves in the earlier ex- 

 periments had sustained the slightest injury, new leaves forming 

 faster than injured leaves fell. Injury upon the leaf is first ap- 

 parent in small and definite reddish-brown spots, which are visible 

 upon both surfaces. The centre of the spot soon assumes a lighter 

 color, and the tissue becomes dead and translucent. The edges 

 of the leaf become discolored in like manner, and show a tendency 

 to curl. A close observation discloses the fact that the discolora- 

 tions take just the shape of the drops or streaks of liquid which 

 lay upon the leaf. These leaves are at once distinguished from 

 any which may suffer from fungous troubles by the absence of 

 raised, puffed, or ragged borders about the spots, and by the 

 presence of the scorched margins. Shoots are injured in the same 

 manner as the leaves. Small bright red spots appear, and blotches 

 mark the course of the liquid as it collected and ran down the 

 stems. The whole shoot soon becomes abnormally red, as if its 

 growth were arrested. Sometimes these shoots die outright, but 

 they oftener survive. When the spraying is very copious, so that 

 the liquid washes the foliage, half or more of the leaf may die 

 outright without becoming much spotted. In such cases the 

 injury is quickly apparent. The liquid runs down the stems freely, 

 and they may suffer sooner than the leaves. In some of the trials, 

 the death of the shoots caused the wilting of the foliage, and the 

 leaves himg loosely for some days. Microscopic examination 

 shows that the cell walls in the dead spots retain their shape, but 

 the protoplasm is dry and shrivelled. The peach leaf has a very 

 delicate structure, the epidermis being remarkably narrow, with 

 thin-walled cells. This delicacy of structure appears to account 

 for the peculiar susceptibility of the peach leaf to injury: the 

 poison quickly permeates the tissue. Leaves injured by London 

 purple were found, upon analysis, after thorough washing, to 

 contain arsenic in the texture of the leaf, while analyses of leaves 

 injured by Paris green showed no arsenic in the texture of the 

 leaf. The poison in the latter case had acted from the surface of 

 the leaf. It is apparent that London purple is the more injurious 

 because of its soluble arsenic. The arsenic in London purple is 

 in the form of a normal arsenite of calcium, which substance com- 

 prises about 73 per cent of the whole compound, and over 50 per 

 cent of it, or nearly 40 per cent of the London purple, is quickly 

 soluble in water. 



