Two other bottles were prepared in a similar manner, with the exception of the lead caps, and were sunk to a depth of 102 fathoms. These bottles were filled with water, and the corks which, previous to immersion, stood nearly half an inch above the necks of the bottles, had been so much compressed as to allow the water to pass round them. One of the corks exhibited this compresssed appearance for a length of time after it was drawn up, leaving the pitch standing like a wall above the neck of the bottle. The next experiment was made in the jolly boat, at some distance from the ship, as on former occasions; when three bottles were sunk to the depth of 150 fathoms, and, consequently, subjected to a pressure of about 450 pounds on the square inch. When drawn up, it was discovered that Mr. Benson's bottle was full of water, and Mr. Rudder's perfectly free from all fluid. The bottle sunk by Mr. Benson was prepared by placing a wooden stay within the bottle, as shewn in figure 4, upon which a cork was firmly driven. The neck of the bottle was then filled with melted pitch, into which a cork was forced down; over the whole was tied a piece of leather, and the neck of the bottle immersed in pitch. Mr. Rudder's first bottle was prepared in a similar manner to Mr. Benson's, excepting that the cork was cut off flush with the neck of the bottle (which, being patent, was consequently true), and, after being dipped in boiling pitch, a halfpenny was imbedded upon the top of the cork. The second bottle had the wooden stay for support to the cork, fixed perpendicularly; and over the above-described stopping a cap of lead, of about one-eighth of an inch in thickness, was secured, and pitched over, excepting on the upper surface of the lead. The appearance of the respective bottles, when drawn up, was as follows: Mr. Benson's bottle had the corks and their covering so compressed that they were nearly three quarters of an inch below the rim of the neck, and the bottle as full of water as bottles usually are of wine. The air in the neck of the bottle, which must have been highly compressed, continued to issue through the pores of the cork for a considerable time after the bottle had been drawn up. In Mr. Rudder's first bottle no alteration was apparent; and in the second the only change that had taken place was the compression of the lead inwards, forming a concavity, of about one-fourth of an inch in depth, in the centre. As the experiments made by Mr. Rudder and Mr. Benson were considered inconclusive, in relation to the question of the porosity of glass, or its permeability by water, (the pressure of a column of water of 900 feet, the depth to which their bottles were plunged, not exceeding a pressure of 450 pounds on the square inch), Mr. Wickenden, with the assistance of an intelligent member of the Institution, proceeded to make the following experiments. Glass balls, varying in size and thickness, were hermetrically sealed, and subjected to a pressure of 1050 pounds on the inch; that is equivalent to the weight of a column of water of about 2000 feet, or 350 fathoms, exceeding the pressure to which the bottles were exposed by 200 fathoms. The integrity of the globes was maintained in this experiment, and not a drop of water entered. In order to submit the globes to the greatest accessible pressure, it was determined to place them in the plunger of Bramah's hydraulic press. The balls, which were three inches in diameter, were inclosed in a box, perforated to admit the water, and after being subjected to a superficial pressure of between eighteen and nineteen tons, or about a ton and a half on the square inch, (which is equal to a column of water of 1120 fathoms, or 6720 feet, that is, a weight of 3360 pounds on the square inch) they were taken out uninjured, and perfectly free from internal moisture. From the whole of the foregoing experiments, the following conclusions may be drawn. 1st. It appears extremely difficult, by stopping the mouths of bottles with extraneous matters, such as cork, wood, pitch, &c., to resist the stupendous weight of columns of water of great altitude. 2ndly. That at a depth of 150 fathoms, or 900 feet,—that is, with a pressure of about 450lbs. on the square inch, glass is not permeable by water. By the experiments made with glass balls, the difficulties of stoping are overcome, whilst a form is employed better adapted to resist the higher degrees of pressure; and the presumptive evidence of the non-porosity of glass, or rather impermeability by water, is greatly increased. The question assumed as proved by Mr. Rudder's experiments, is the non-porosity of glass. The transmission of light and magnetic influence through this substance might, perhaps, be considered as sufficient evidence of such structure. A more accurate statement of the object of these experiments, therefore, would be to prove the impermeability of glass by water under high degrees of pressure.— Were it possible for glass balls to resist the sudden expansion and heat of steam, the proof required would be more probably attained by the tenuity of the elastic vapour of water, than by the same fluid under the most severe pressure. In one of Mr. Rudder's experiments, it was observed that the cork had been forced into the bottle, and was seen floating on the surface of the water which half filled the bottle, and upon replunging the bottle to the same depth, 112 fathoms, the vessel filled and the cork was replaced. The replacement of the cork as originally inserted, or reversed, so far as position is concerned, is purely accidental; when the cork, by equal pressure, has been so far reduced in all its dimensions that either end of it would enter into the neck of the bottle, that part would be certain to be uppermost, which presented itself to the neck, during the ascent of the bottle. It may not, perhaps, be considered altogether irrelevant to the present subject, to allude to the astonishing power of the whale to resist pressure. When struck with the harpoon, the whale dives perpendicularly, and the quantity of line they sometimes take out of the boat, in a perpendicular descent, Captain Scoresby considers a good measure of the depth. By this rule, they have been known to descend a mile; bearing, consequently, a pressure of one ton and a quarter on every square inch; which multiplied by the extent of surface of the animal, varying in length from 60 to 200 feet, and of proportionate width, gives an amount almost incredible-720,000 tons! It is very reasonable to enquire if there be any provision in the structure of diving animals, to enable them to sustain such pressure. In a paper read by Mr. Houston, at the late Meeting of the British Association, "On Peculiarities in Circulating Organs of Diving Animals," it was observed that circulation, though principally carried on and continued by the vital principle, and ceasing altogether when that principle becomes extinct, was to some extent amenable to the laws of hydraulics. The circulation through a limb is affected by position; the removal or increase of atmospheric pressure is known to affect the circulation of the skin; the action of the air and chest, during respiration, also modify the circulation. It is a well-established fact that a whale can suspend respiration for twenty minutes, and sink to the depth of an English mile in the ocean. The effect of the interrupted respiration and increased external pressure, must necessarily be an alteration in the circulation, which, unless met by a suitable provision, must prove inconvenient, if not fatal, to the animal. That such a provision existed, Mr. Houston was prepared to prove; it existed in the enormous size and complexity of the venous system, particularly in the right cavities of the heart, the vena cava, the hepatic veins, and those of the abdominal and spinal canal. These facts were illustrated by some elegant preparations of the injected venous system of the seal and porpoise. The subject was farther pursued, and the circulation of some animals possessing the power of suspending respiration for a less considerable time, was examined; the result was highly satisfactory --and it was proved, by demonstration, from several specimens, that the enlargement of the heart and venous system was proportionate to the power of suspending respiration. Several new facts were adduced, both in comparative anatomy and pathology, which would appear highly confirmatory of Mr. H.'s physiological views as stated in the communication. SONNET. GUIDE me, O God, as with a father's hand, The sigh scarce-breathed, the heart's unlettered prayer,— My best affections to thyself unite And let thy favour be my chiefest care. E. S. 78 A RETROSPECT OF THE LITERATURE OF BRITISH ORNITHOLOGY, FROM THE CLOSE OF THE 17TH CENTURY TO THE PRESENT TIME. THROUGHOUT the whole extensive domain of Nature, there is nothing which can more deeply interest and delight the inquisitive and reflecting mind than the study of Birds. That, from the earli est ages, these beautiful animals should have, in an especial way, attracted the notice of Man, no one, even slightly acquainted with their structure and economy, and the wonderful instincts which they exhibit in their architecture and migrations, can, for a moment, feel surprized. Their size and symmetry, the elegance of figure, the splendour of plumage, the power and rapidity of flight, and the melody of song which many of them possess,-the astonishing industry and skill, the exemplary patience and solicitude, affection and courage which they almost invariably display in the construction of their nests, and the rearing and protection of their helpless young, are such as must have arrested the eye of the more careless observer, and occasionally stirred up even the most torpid brain from its habitual slumbers. Hence, it has happened that, in all times and countries, Birds have, more frequently than any other part of the animal creation, employed the descriptive powers of the Natural Historian, and the pencil of the Artist. Yet an examination of the ornithological writings of the British Naturalists of the eighteenth century is, unfortunately, far better calculated to propagate error than afford correct information,-to promote the interests of the Author and "the Trade," rather than those of truth and science. Let any one read over the fabulous accounts of the hyëmal submersion of the Swallow,-the miraculous stories which are told of the properties possessed by the carcase of the splendid King-fisher, and the elegant little wren,-of the extrication of the Bernacle Goose from the Lepas or Bernacle shell,— all gravely narrated,-aye, and manfully sworn to upon the four Gospels, by eye-witnesses, of reputable character and reputed ve |