p 



May lo, 1877] 



NATURE 



25 



metically sealeJ, and after a lapse of time on opening the vessel 

 the organisms were found in a living state, they must have arisen 

 de luv;'. That is, the not living would have produced the living ; 

 that this method is useful, and that it must be pursued in an ex- 

 haustive inquiry into the whole subject, must be freely admitted. 

 But that it is the best, or at least the only, method of inquiry 

 for the biologiit we may gravely doubt. 



Ten years ago Mr. Dallinger detern\ined to endeavour to work 

 out by actual microscopic observation the life history of some of 

 the lowly life forms. 



After four years spent in preparation he commenced his work 

 in conjunction with Dr. Drysdale, the plan needing two ob- 

 servers. A characteristic feature of the work was that each set 

 of observations should be made .absolutely continuous, so that 

 nothing should have to be inferred. An arrangement was made 

 by which the little drop of septic lluid containing the objects 

 under examination should be free from evaporation, and very 

 high powers were employed. The largest adult objects included 

 in the examination were the one-thousandth of an inch, the 

 smallest adults were the four-thousandth. Six forms altogether 

 were selected, and, by long, patient, and unbroken watching, 

 their whole history was worked out. While reproduction by 

 fission seemed at first to the observers to be the usual method, 

 prolonged research made known that spores were produced. 

 These wcie so small that a ni ^i.ifying power of 5,000 diameters 

 was needed to see them as tney began to grow. The glairy 

 fluid from which they developed seemed at first homogeneous, 

 and it was only when growth set in that the spores became visible. 

 All that could be leanit about the origin of the glairy fluid was 

 that a monad, larger than usual, and with a granulated aspect 

 towards the flagellate end, would seize on one in the ordinary 

 condition. The two would swim about together till the larger 

 absorbed the smaller, and the two were fused together. A mo- 

 tionless spheroidal glossy speck was then all that could be seen. 

 This speck was found to be a sac, and after remaining still for 

 from ten to thirty-six hours it burst, and the glairy homogeneous 

 fluid (lowed out. The young spores that came into view in this 

 were watched through to the adult condition. Bearing on the sub- 

 ject of spontaneous generation, this fact was learnt, that while a 

 temperature of 140° F. was sufficient to cause the death of adults, 

 the spores were able to grow even after having been heated to 

 300' F. for ten minutes. Can it be philosophical, Mr. Dallinger 

 asked, with the life history of bacteria still unknown, to assume 

 it as a different method of propagation ? Some experiments 

 based on Prof. Tyndall's use of the electric beam to test optic- 

 ally pure air were made. The remains of infusions known to 

 contain certain spores were diffused through glass tubes, in which 

 were placed vessels with fluid. Monads always appeared in the 

 fluids, but when after the air in the tubes had been allowed 

 to purify itself by settlement, fresh fluids were introduced, no 

 monads appeared. That there is no such thing as spontaneous 

 generation of monads seems quite clear, and when bacteria are 

 in like manner studied, there can be hardly a doubt the same law 

 will be found to hold good with them. 



GREA T GUNS 



TT is natural that at the present time great interest 

 ••■ should be taken in all efforts to improve, that is, to 

 render more destructive, our implements of war. Even 

 since the last war on the European field great advances 

 have been made in this direction ; and, as our readers 

 know, one of the largest guns ever constructed is at pre- 

 sent on its trial in this country. Some months ago ex- 

 periments were made with what is known as the 81-ton 

 gun, the invention of Mr. Robert Fraser ; the gun was 

 sent back to Woolwich for some alterations to be made, 

 and on Friday the experiments were resumed at Shoe- 

 buryness on a larger scale. On the previous occasion the 

 gun was loaded with 370 lbs. of powder, and threw a blind 

 Palliscr shell against the target. This target is of enor- 

 mous strength, as strong and firmly founded as the in- 

 genuity of engineers can make it. It is formed 

 of four plates of the best rolled iron, each plate being 

 8 inches thick, and 5 inches of solid teak filled up 

 each of the three intervals between the four plates. The 32 

 inches of iron and 15 inches of teak thus placed are solidly 

 screwed together by bolts 3 inches in diameter, the whole 



forming, as far as scientific engineers and artillerists could 

 construct it, an apparently impenetrable and immovable 

 mass. To secure the target still more, iron plates were 

 placed on the top and at the side, those at the side being 

 strutted against the target with heavy timbers ; and the 

 supports at the rear of the target, to hold it up, as it were, 

 against any blow, were of the like solid and substantial 

 character. 



The target stood at 120 yards' distance from the gun. 

 On Friday the charge of powder was 425 lbs., and the 

 weight of the blind Palliser shell 1,700 lbs. At the base 

 of the latter was an expanding copper-ridge, known as 

 the " Lyon " gas-check, which in the explosion would ex- 

 pand and fill the rilling, thus enabling the full energy of 

 the exploded powder to be utilised. 



After the gun was fired, by electricity, it was examined 

 and found to have worked admirably ; it had run back 

 55 feet on its tramway, which rises slightly, and had run 

 down again to the firing-point. The shot was found not 

 only to have penetrated three plates and the teak intervals 

 to all four, as on the previous occasion, but to have bulged 

 out the fourth plate some 15 inches from its normal posi- 

 tion. The last plate was, moreover, broken across, the 

 edges of the broken part gaping wide, and showing the 

 head of the shot, which had thus penetrated further in 

 distance than the 47 inches of iron and teak of the target. 

 The powerful framework behind the target was greatly 

 shaken. The shot itself had " set-up," /.,-., closed towards 

 the head with the enormous energy, the rear-part, the 

 gun-metal studs, and the copper gas-check, crumbling 

 into pieces. The initial velocity of the shot, as registered 

 by M. Le Boulenger's invention of wires with electric 

 communication was 1,600 feet a second, and the striking 

 velocity 1,585 feet. The mean pressure on the gun was 

 found to be 20 tons, the interior remaining quite unaltered. 

 Herr Krupp, the well-known Prussian artillerist, has 

 been devising a weapon even more formidable than that 

 whose power of destruction was shown on Friday to be 

 so immense. The Fraser gun is of wrought iron, but the 

 new Krupp gun is of cast-steel, both being very nearly ot 

 the same weight, though the latter has the great advantage 

 over the former of being a breech-loader. The length of 

 the gun, including the breech-picce, is 29 feet 6 inches, 

 the bieech-piece itself being 6 feet 4 inches in length. 

 The calibre of the gun is 15 j inches. The weight of the 

 projectile will be 750 kilogrammes, or 1,650 lbs., and the 

 powder charge will be 396 lbs. The external diameter of 

 the Krupp gun, independently of a narrow strengthening 

 ring at the extreme rear, is 5 feet 10 inches, that of the 

 Fraser gun being 6 feet. The core of the Krupp gun is 

 a steel tube in two lengths, upon which four steel rings 

 overlap, rising in steps from a point between the muzzle 

 and the trunnions, and accumulating in the thickness 

 towards its rear. These more massive rings are irre- 

 spective of the narrow strengthening ring over the powder 

 chamber. The external diameter of the gun at the muzzle 

 is 2 feet 3i inches. 



In common with the other large Krupp guns, the rifling 

 of the new weapon is on the polygroove system, the elon- 

 gated projectile being rotated by means of the gas-check. 

 The velocity anticipated from the projectile fired from 

 the Krupp 80-ton gun is 473 metres per second at the 

 muzzle, or 1,552 feet, producing an energy of 27,543 

 foot tons, equal to 556 foot tons per inch of shot's circum- 

 ference. 



But this is not all. Should the demand arise, the great 

 Prussian gun-maker has a design already prepared for a 

 gun of 124 tons, to be made on the same plan as the one 

 just described. The larger weapon would have a calibre 

 slightly exceeding 18 inches, and would throw a steel 

 shell weighing 1,000 kilogrammes, or a chilled iron shell 

 of 1,030 kilogrammes. The weight of the projectile would 

 therefore be practically a ton, and the charge of powder 

 will be probably about 500 pounds. 



