THE EDINBURGH JOURNAL OF NATURAL HISTORY. 



GENERAL SCIENCE. 



On tke Use of Nicol's Calcakeous Spar, Prism xs discovering Shoals 

 jv THE Ocean. — It has been remarked by M. Arygo, that the bottom of the sea, 

 or the surface of a shoal at a given distance from a skip, is more distinctly seen 

 from its mast-head, or, generally speaking, from a considerable height, tha:: from the 

 deck. He explains this phenomenon on the principle that the re-flectied li,'j:ht from 

 the surface of the sea, which is always intermixed with that from the bottom, or the 

 shoal, possesses a less and less degree of intensity in proportion as the angle of re- 

 flection, reckoned from the surface, is lax-ger. That this reflected light may be entirely 

 removed, when looking into the sea to discover cliffs or shoals, &c., he proposes to 

 observe them by means of a Tourmaline, in which the axis is held horizontally, if 

 possible under a polarizing angle of 37", reckoning from the surface. The entire 

 and absolute obstruction of the light reflected from the surface of the water cannot 

 possibly take place under a smaller angle than 70'', because it is under this angle 

 alone that it is completely polarized; but under angles of 10" or 12" greater or less 

 than 37", the number of polarized rays which the Tourmaline can arrest is still so 

 considerable, that the same means of observation cannot fail to be attended with 

 very advantageous results. Poggendorf proposes to use for this important purpose, 

 instead of the TouvmaUne, Xs'^icol's Calc Spar Prism, because, from its being colour- 

 less, it is much better fitted for the purpose. By engaging in such experiments, 

 Arago remarks, that " Mariners will throw a light on a curious question of Photo- 

 metry; they will probably confer on navigation a means of observation which may 

 prevent many shipwrecks ; ard by introducing Polarization into the nautical art, they 

 will afford an additional proof of what those individuals expose themselves to, who 

 unceasingly collect experiments and theories without any practical application of 

 them, meeting every remonstrance with a contemptuous cui bono." Ere long, we 

 doubt not, ships generally, at least all those vessels specially occupied in geographical 

 and hydrographical researches, will, before leaving port, be provided with Nicol's 

 valuable little instrument. 



The Effects of Coivipressed Air on the Human Body. — Dr Junod has 

 communicated to the Academy of Sciences the results of his experiments with com- 

 pressed air. In order to operate on the whole person, a large spherical copper 

 receiver is employed, which is entered by an opening in the upper part, and which 

 has a cover with three openings — the first for a thermometer, the second for a baro- 

 meter or manometer, and a third for a tube of communication between the receiver 

 and the pump. The air in the receiver is perpetually renewed by a cask. "When 

 the pressure of the atmosphere is increased one half, the membrane of the tym 

 panum suffers inconvenient pressure, which ceases as gradually as the equili- 

 brium is restored. Respiration is carried on with increased facility; the capacity 

 of the lungs seems to increase; the inspirations are deeper and less frequent. 

 In about eighteen minutes an agreeable warmth is felt in the interior of the thorax. 

 The whole economy seems to acquire increased strength and vitality. The in- 

 creased density of the air appears also to modify the circulation in a remarkable 

 manner ; the pulse is more frequent, it is full, and is reduced with difficulty ; 

 the dimensions of the superficial venous vessels diminish, and they are some- 

 times completely effaced, so that the blood in its return towards the heart follows 

 the direction of the deep veins. The quantity of venous blood contained in the lungs 

 ought then to diminish, and this explains the increased breathing of air. The blood 

 there is then determined in a larger quantity to the arterial system, and especially to 

 the brain. The imagination becomes active, the thoughts are accompanied with a 

 peculiar charm, and some persons are affected with symptoms of intoxication. The 

 power of the muscular system is increased. The weight of the body appears to dimi- 

 nisli. When a person is placed in a receiver, and the pressure of the air is diminished 

 one-fourth, the membrane of the tympanum is momentarily distended; the respira- 

 tion is inconvenienced, the inspirations are short and frequent, and in about fifteen or 

 twenty minutes there is a true dyspnoea. The pulse is full, compressible and fre- 

 quent ; the superficial ve-^sels are turgid. The eyeballs and lips are distended with 

 superabundant fluids, and hemorrhage and tendency to syncope are sometimes in- 

 duced; the skin is inconveniently hot, and its functions increased in activity; the 

 salivary and venal glands secrete their fluids less abundantly. 



REVIEWS. 



The Edinburgh Neiv Philosophical Journal, exhibiting a view of the progressive 

 Improvements inthe Sciences and Arts, conducted by Profesaor Jameson, No. 42, 

 Juli/ — octavo^ 1836. Edinburgh : Adam and Charles Black. 

 The present Number of this Work contains a great variety of interesting articles, 

 and none more so than that by M. Elie de Beaumont, "on the Temperature of 

 the Earth's Surface during the Tertiary Period ;" and also the article by Leopold 

 Von Buch " on Volcanos and Craters of Elevation." The object of this, paper is to 

 show, that Craters of Elevation are not Volcanos ; that there is a well grounded and 

 important distinction between the two ; and that even the cones of Volcanos can be 

 formed only by a sudden elevation, and never by the building up of streams of lava. 

 He considers that Volcanos are the constant chimneys, the canals uniting the interior 

 of the errth with the atmosphere, which spread around themselves the phenomena 

 of irruption from Craters that axe. of small extent, and are only once in operation ; 

 while Craters of Elevation, on the contrary, are the remains of a great display of 

 powers from within, which are capable of, and actually have raised islands of several 

 square miles in extent, to a considerable height. In a future Number we shall 

 present in detail the views of Von Buch on this highly mteresting subject. 



The paper by M. Charpentier " on the Glaciers of the Canton of Vallais," contains 

 some remarkable facts respecting the formation and decomposition of Glaciers. One 

 of these we think deserving of notice ; namely, that the mass of a Glacier consists of 

 ice, or rather frozen snow, in a pure state, without any mixture of earth or slones. 

 When blocks fall through a fissure to the bottom of the Glacier, they are rolled or 

 pushed forward. If they remain hemmtid in between the walls of the fissure, they 



apppear again after a lapse of a certain period of time on the surface of the GUcier, 

 but at a point farther down the valley than where they fell in. When, however, a 

 block falls quite near the lower end of a Glacier through a fissure to the bottom, and 

 at a time w hen the Glacier is retiring, it remains nearly at the same point and in the 

 same position which it occupied when it fell, 



Bache's paper on the alleged influence of colour on the radiations of non- 

 luminous heat contains a series of important experiments, the results of which are 

 decidedly unfavorable to the specific efi'ect of colour, in determining the radiating 

 powers of bodies ; and if the results be admitted as decisive of the radiating powers 

 of the bodies used, they show, that each substance has a specific power not depending 

 upon chemical composition nor upon colour. 



Assistant- Surgeon Jameson's notes on the Natural History and Statistics of the 

 Island of Cerigo, in the Mediterranean, are full of new and interesting information r, 

 and Dr Graham's Botanical Excursion acquaints us with a number of new localities, 

 in which the rarer plants of our native Flora have been discovered. 



This Number contains a very full account of the pioceedings of the British As- 

 sociation at Bristol in August 1836 ; and the Miscellaneous information contained in 

 the Scientific Intelligence is full and varied. 



The Edinburgh Philosophical Journal was commenced in June 1819, and has 

 been continued uninterruptedly, by Professor Jameson, up to the present time. It 

 IS but justice to say, that no European work, which has appeared during the same 

 series of years, contains so full and varied accounts of the progress of the Sciences 

 and Arts as it does. It is an indispensable companion to the Library of all who study 

 the Physical Sciences, and the advancement of the: useful arts. 



OBITUARY. 



Mr Edward Turner Bennet. — Natural History has met with an incalculable 

 loss by the death of Mr Bennet, who died on Sunday the 21st August, 1836, after 

 a very short illness. He was Secretary to the Zoological Society, which oface he 

 filled with much credit to himself, and with great advantage to the Society. The 

 scientific labours which this gentleman undertook, in addition to his official capacity, 

 was to watch and detail the habits of the living Mammalia in the Gardens of the 

 Society, Regent's Park. This task he performed with distinguished ability, which 

 is borne out by his papers in the "Zoological Journal," brought out mainly 

 by his able support and influence. He was also author of those excellent works 

 the *' Town Blenagerie," and the " Gardens and ]\ienagerie of the Zoological So- 

 ciety," of which we have spoken in high terms, in our notice at page 48 of this 

 Journal. 



Mr David Douglas. — It is with extreme regret that we have to announce the 

 death of this indefatigable and excellent young man ; and more especially the melan- 

 choly accident which led to it. flir Douglas was engaged by the Horticultural So- 

 ciety of London to travel in various countries as a Naturalist ; and has in his journeys 

 been very successful in discovering many new plants, and various Mammalia and 

 Birds ; especially on the Western territories of North America. He was engaged in 

 his scientific pursuits when he met with the fatal accident, which took place on the 

 12th July 1834. The cause of his death is thus recorded in the Ke Kamu Hawaii, 

 printed at Honolulu, of 26th In^ov. 1834 : — " From Edward Gurney, an Englishman, 

 we received the following account of the tragical scene : About ten minutes before 

 six o'clock in the morning, Mr Douglas arrived at his house in the Mountain, and 

 wished him to point out the road to Hilo, and to go a short distance with him. Mr' 

 Douglas was then alone, but said that his man had gone out the day before (this was 

 probably John, Jlr Deill's coloured man). After taking breakfast, Edward accor- 

 panied Mr Douglas about three-fourths of a mile, and after directing hira on the path, 

 and warning him oif the traps, went on about half a mile farther with him. J\Ir 

 Douglas then dismissed hira, after expressing an anxious wish to reach Hilo that eveis- 

 ing, thinking that he could find out the way himself. Just before Edward left him, 

 he warned hira particularly of three Bullock traps, about two miles and a half a-head, 

 two of them directly on the road, the other on the side. Edward then parted with 

 Mr Douglas, and went back to skin some bullocks w^hich he had previously killed. About 

 eleven o'clock, two natives came in pursuit of him, and said that the European was dead, 

 and that they had found him in a pit in which the bullock was. They mentioned that they 

 were coming up to this pit ; one of them observing some of the clothing on the side, ex- 

 claimed lole, but in a moment afterwards discovered Mr Douglas within the cave, trampled 

 under the feet of the bullock. They went off immediately for Edward, who left his work, 

 ran to the house for a musket and ball, and hide, and on coming up to the pit, found 

 the bullock standing on Rlr Douglas's body. Mr Douglas was lying upon his right side. 

 He shot the animal, and after drawing him to the other end of the pit, succeeded in 

 getting out the body. His cane was with him, but the bundle and dog were not. 

 Edward knowing that he had a bundle, asked for it. After a few moments' search, 

 the dog was heard to bark, at a short distance a-head, on the road leading to Hilo. 

 On coming up to the place, he found the dog and the bundle. On further exami- 

 nation, it appeared that Mr Douglas had stopped for a moment and looked at the 

 empty pit, and also at the one in which the bullock had been taken ; that after pass- 

 ing up the hill some fifteen fathoms, he laid down his bundle, and went back to the 

 pit in which the bullock was entrapped, and which lay on the side of the pond oppo- 

 site to that along which the road runs ; and that whilst looking in, by making a mis- 

 step, or by some other fatal m.eans, he fell into the power of the infuriated animal, 

 who speedily executed the work of death." Thus has perished a Naturalist who has 

 travelled over a wide extent of country, and who, from his zeal, must have collected 

 an immense number of facts which could not fail to have been of much use to science. 



Edinburgh: Published for the Proprietors, at their Office, 16, Hanover Street, 

 London: Smith, Elder, and Co., 65, Cornhill. Glasgow and the West of 

 Scotland: John Smith and Son; and John Macleod. Dublin: W. F. 

 V/aki^man. Paris: J. B. Bai.lieke, Ruedel'Ecole de Medecine, No. ISbi^. 



THE EDZNIIL'KGH TUINTING COJIPANY. 



