Meteorological Observations made in connexion with the Balloon Ascent on October 2, 1865.-ROYAL OBSERVATORY, GREENWICH. Meteorological Observations made in connexion with the Balloon Ascent on Report on the Extinct Birds of the Mascarene Islands. By a Committee consisting of Professor A. NEWTON, Rev. H. B. TRISTRAM, and Dr. SCLATER. ALMOST immediately after the appointment of the Committee, intelligence was received in England of the very important discovery by Mr. George Clark, of Mahébourg, in Mauritius, of a large deposit of bones of the true Dodo (Didus ineptus), in a marsh known as the Mare aux Songes,' an account of which that gentleman has published in The Ibis' Magazine for April 1866. Several fine series of these bones having been sent to England, some were purchased by the Trustees of the British Museum, and formed the subject of a memoir " On the Osteology of the Dodo," read by Professor Owen at a meeting of the Zoological Society of London, 9th January, 1866. This memoir is understood to be nearly ready for publication, and will appear, copiously illustrated, in the Transactions of that Society. Some other fine series of these bones have, by the liberality of Mr. Clark, passed into the possession of one of the members of your Committee; and a portion of them is now exhibited. Several smaller series of bones have likewise been variously distributed by sale or gift both in England and on the Continent, so that numerous Museums (one of these smaller series forms the subject of some Remarques" communicated to the Academy of Sciences of Paris, 23rd April, 1866. 66 2 D 1866, by M. Alphonse Milne-Edwards) and collections have reaped the benefit of Mr. Clark's valuable discovery, the importance of which may be better appreciated when it is remembered that previously the only remains of the Dodo known to naturalists were the head and foot at Oxford, the skull at Copenhagen, the portion of an upper mandible at Prague, and the foot in the British Museum. Now it is believed that every bone of the bird's skeleton has been recovered, with the exception (though that is an important exception) of the extremity of the wing. The attention of Mr. Edward Newton has been especially called to this deficiency, which seems likely to be supplied by a thorough and systematic examination of the Mare aux Songes, or at least the part of it which has been most prolific in Dodos' bones. That gentleman has accordingly determined to carry out this undertaking as far as may be expedient; but according to the latest accounts received from him, he had been obliged to defer commencing operations in this quarter till the expiration of the rainy season, as the marsh still continued to hold much water, and he expected to be able to do no real good there until next month, when the Committee hope that complete success may attend his excavations. The collection of bones formed in Rodriguez last year by Mr. George Jenner, and sent home by Mr. Edward Newton (as stated in the communication made by that gentleman to this Section at Birmingham) arrived safely in England in the course of the autumn; and the majority of them proved to belong to the Solitaire or Dodo, peculiar to that island (Pezophaps solitaria). They were exhibited at a meeting of the Zoological Society, 23rd November, 1866; and a select series of specimens from them is now produced, among which are several that were previously unknown-such as the proximal end of the tibia, portions of the pelvis and coracoid, the ulna, radius, and phalanx. Mr. Edward Newton has been very desirous of completing the exploration of the caves in Rodriguez, in the hope of finding the remaining portions of the Solitaire's skeleton; but communications between that island and Mauritius being suspended for a large portion of the year, and when existing, being uncertain, the difficulties in the way of carrying out his design were much increased. At last, after long delay, he was informed that labourers were so scarce in Rodriguez that the necessary assistance was not to be obtained for making excavations there. To meet this new and unexpected difficulty he was compelled to hire men in Mauritius and send them to Rodriguez, under engagement for the express purpose of digging in the caves. Committee trust that the best results may follow this mission. The Bourbon or Réunion, the third of the Mascarene Islands, which is known to have formerly possessed a Didine bird, has not been neglected by the Committee; but they regret to say that at present they see no chance of successfully carrying on researches there. Mr. Edward Newton, however, is thoroughly alive to the importance of discovering the remains of this species (of which, unlike its allies, not a single relic is on record as now existing); and he has commissioned a gentleman, who has lately proceeded thither, to make a preliminary survey in the hope of finding places likely to reward a search for its remains. Report on various Experiments carried out by Captain W. H. NOBLE, R.A., under the direction of the Ordnance Select Committee, relative to the Penetration of Iron Armour Plates by Steel shot, to which is added a Memorandum on the Penetration of Iron-Clad Ships by Steel and other Projectiles. [A communication ordered to be printed among the Reports.] IN 1862 the Special Committee on Iron proposed a series of experiments for the purpose of ascertaining whether the penetration of projectiles into iron was proportional to their vis viva. The guns proposed for use were the 68-pounder smooth-bore, and 7-inch BL rifled gun, and the necessary charges were determined by the Ordnance Select Committee with the aid of Navez's Electroballistic Apparatus. A few experiments were subsequently made; but the results were not to be relied on, as the projectiles used were cast iron and broke up on impact. This subject was revived in 1864 by the Ordnance Select Committee, and a series of experiments were authorized for the purpose of determining the following points: First. To determine the relative penetrating effects of two shots on an iron plate, provided they strike with the same "work"*, notwithstanding that the one may be heavy with a low velocity, and the other light with a high velocity. Secondly. To determine the relative resistances of a plate to penetration by two shots of similar form of head, and striking with "work" proportional to their respective diameters. An example of the first point may be stated as follows:-The 10"-5 wrought-iron gun of 12 tons is fired at an iron plate with a charge of 50 lbs., and spherical steel shot of 1684 lbs., the velocity at 200 yards being 1576 feet, and consequent "work" 2898 foot-tonst. The same gun is fired in its rifled state at a similar plate, with a charge of 40 lbs., and hemispherical-headed steel elongated shot of 300 lbs., the velocity at 200 yards being 1180 feet, and consequent "work" 2898 foot-tons. Will the penetration‡ be the same in both cases? The following case will serve to illustrate the second point: The 100-pounder smooth-bore gun of 64 tons is fired at an iron plate with a charge of 15.4 lbs., and spherical steel shot of 104.1 lbs. weight and 8.87 inches diameter, the velocity at 100 yards being 1254 feet, and consequent "work" 1135 foot-tons. The 7-inch M L rifled gun of 130 cwt. is fired at a similar plate, with a charge of 13.5 lbs., and elongated hemispherical-headed steel shot of 100-3 lbs. weight and 6.92 inches diameter, the velocity at 100 yards being 1129 feet, and consequent "work" 886 foot-tons. Will the penetration‡ be the same in both cases, the vis viva being proportional to the respective diameters, or as 8.87 to 6.92? g=the accelerating force of gravity. ↑ Vis viva has been given in foot-tons instead of foot-pounds, in consequence of the number of figures required to express the latter. By penetration is meant actual perforation through the plate, or the power of passing through the plate. In the case of penetration into iron plates the term "indent" has been used. The experiments which the Ordnance Select Committee instituted for the purpose of obtaining a solution to the foregoing questions must be regarded as preliminary to any inquiry into the larger question of the penetration of iron defences by steel projectiles. No attempt has been made to found any absolute law of resistance upon the following results; for these results are not sufficiently extensive to warrant any such proceeding. They were carried out for the purpose of affording a practical solution to the questions at issue, and were limited in extent by considerations of expense. To found any general law of penetration into iron defences would require a much more extensive and costly trial; and although the results of such an investigation might be highly interesting as a philosophical question, it is doubtful whether they would prove of sufficient practical utility to warrant the unavoidable expense*. When it is considered that this question is surrounded by difficulties and causes of error over which we have no control, it will appear that it is at present hopeless to look for anything but an approximate result. The very quality of the materials we are obliged to make use of, the rough and practical nature of the trials, and the necessity of carrying them out on a moderate scale, all tend to make the experiments, philosophically considered, imperfect and insufficient as a basis for mathematical analysis. The following programme of experiments was determined on for the first point: Gun.-6.3-inch M L rifled gun (Shunt†). Projectiles.-Four descriptions of steel shot, of the following weights, as nearly as manufacturing limits will allow :-spherical 35.5 lbs., elongated 71 lbs., elongated 106.5 lbs., elongated 64 lbs.‡,—all to be hemisphericalheaded, and of 6.22 inches diameter. Charges. To be so arranged that each projectile may strike with the same "work" stored up in it. Iron Plates.-Best rolled iron, 5 inches thick, placed vertically at a distance of 100 yards, and unbacked. The programme for the second point was as follows: : Guns.-6.3-inch M L rifled gun of 140 cwt.; 7-inch M L rifled gun of 134 cwt.; 100-pounder smooth-bore gun of 61 tons (9-inch). Projectiles §.-For 6.3-inch gun, same as detailed in the first programme; for 7-inch gun, elongated steel shot of 100 lbs. weight and 6-92 inches diameter; for 100-pounder gun, spherical steel shot of 104 lbs. and 8.87 inches diameter. Charges. To be so arranged that each projectile may strike with a “work” proportional to its diameter, taking the 6-3-inch as the standard. Iron plates.-Best rolled iron 5 inches thick, placed at a distance of 100 yards, and unbacked. *The experiments hitherto carried out have given us a fair practical knowledge of the conditions to be fulfilled in order that complete penetration through iron defences may be effected. We can predict, with a very close approximation to the truth, whether a given projec tile striking with a given velocity, will or will not perforate a given iron structure; but supposing it not to be able to perforate it, we cannot say how far it will indent it, and it is submitted that this is of little consequence. The gun used in the first series of experiments against 5.5-inch plates was the experimental 6.3-inch gun of 140 cwt., length of bore 126 inches. This enabled the necessary high velocity to be obtained. Same weight as service-shot. § Elongated projectiles were all hemispherical-headed. |