ARTICLE IV. SCIENTIFIC INTELLIGENCE; AND NOTICES OF SUBJECTS I. Lectures. Mr. Clarke will commence his next Course of Lectures on Midwifery, and the Diseases of Women and Children, on Wednesday, Jan. 24. The lectures are read every morning, from a quarter past ten to a quarter past eleven, for the convenience of students attending the hospitals, at No. 10, Saville-row. Dr. Clutterbuck will begin his Spring Course of Lectures on the Theory and Practice of Physic, Materia Medica, and Chemistry, about the middle of January, at ten o'clock in the morning, at his house, No. 1, in the Crescent, New Bridge-street. Medical Theatre, St. Bartholomew's Hospital. - The Spring Courses of Lectures will commence at this place on Saturday, Jan. 20-On the Theory and Practice of Medicine; by Dr. Hue.-On Anatomy and Physiology; by Mr. Abernethy.-On the Theory and Practice of Surgery; by Mr. Abernethy.-On Chemistry and Materia Medica; by Dr. Hue.-On Midwifery; by Dr. Gooch the Anatomical Demonstrations by Mr. Stanley. Russell Institution.-A Course of Lectures on the Elements of Electrical Science, including Galvanism and Electro-Chemistry, will be delivered at the Russell Institution during the ensuing season, by Mr. Singer. II. Geological Remarks on different Parts of Scotland: being an Extract of a Letter to the Editor from Professor Jameson. In my journey of this summer I revisited several points on the east coast of Scotland, re-examined the beds of porphyry and trap tuff in red sand-stone at Bervie, Crawtown, &c. discovered serpentine with imbedded diallage in the green-stone of the red sand-stone formation at Bervie, and found the Gabbro rock in situ at Portsoy, the andalusite near Macduff, the Hyperstene of Hauy at Portsoy; the great quartz formation which extends from Portsoy by Cullen nearly to Buchie, in which I observed beautiful illustrations of the chemical nature of the quartz breccias, and conglomerates of this and other parts of Scotland. Viewed the conglomerate rocks and red sandstone of Inverness; but only in a general way, as my intelligent friend Professor Buckland, of Oxford, had promised to examine them particularly. Found the conglomerate and red sand-stone extending nearly to the face of Fyers on the south side of Loch Ness, when they are succeeded by primitive rocks, which continue to Fort Augustus. The conglomerate rocks of Inverhavicket, and those near Fyers, are particularly interesting. The gneiss rocks at Fort Augustus abound in beds and veins of granite. A conglomerate rock appears again on the road from Fort Augustus to Letter Find lay, and contains beds and veins of granite. I remained several days at Fort William waiting for clear weather to ascend Ben Nevis; but the continuation of the fog and the rain confined my labours to the examination of Glen Nevis and the base of Ben Nevis. The beds of granite, syenite, and porphyry, are truly magnificent, and in a geognostic point of view highly interesting. Near Balahelish ferry, noticed various alternations of clay-slate with lime-stone; vast beds of quartz and trap. The country around Mr. Stewart, of Balahelish, I knew from my young friend Mr. Walter Adam to be well deserving the particular attention of the mineralogist, and the few hours I spent there proved highly gratifying to me. The geognostic relations of the granite, syenite, porphyry, quartz, and other rocks, correspond with those I observed in Glen Nevis. At the great slate quarries belonging to Mr. Stewart I observed fine examples of clayslate in distinct concretions of various magnitudes and forms, and which appeared to me to be illustrative of the chemical nature of clay-slate. Glenco exceeds in grandeur and magnificence all the mountainous scenery I have hitherto visited in Scotland. In this valley a great bed of a singular rock attracted my particular attention. It is composed of red granite, syenite, and porphyry, intermixed with enormous masses of quartz, which is sometimes pure, sometimes mixed with felspar or with mica; and it is to be observed passing into granite, or into gneiss, or mica-slate. This curious mass has sometimes a conglomerated character; and, when not viewed on the great scale, might in some places be considered as granite, in others as quartz rock, or gneiss, or mica-slate, or porphyry; whereas the whole enormous mass is probably a conglomerated bed belonging to the mica-slate or clay-slate formation. The upper part of this glen, as remarked by Dr. Macknight, presents a grand display of porphyry rocks, and also those of the syenite formation; and few quarters in Scotland afford so fine a field for the study of their various geognostic relations. Here, as in Glen Nevis, &c. many appearances occur which show how cautious we ought to be in inferring the relative position of rocks from the direction and dip of the neighbouring strata. From the dreary inn of King's House the geognost can examine with ease the grand granite and syenite mountains that extend to Glenco and Inverouran; and at this latter place the connexion of the gneiss with these rocks can be satisfactorily ascertained. I spent some time in examining the lead mine in the vast bed of quartz at Tyndrum. The great conglomerate cliffs at Callender are trap tuff. It alternates with old red sand-stone. In Roxburghshire I find the predominating rocks to be greywacke-slate, greywacke, transition clay-slate, and red sand-stone, with its subordinate rocks. The transition rocks in this county agree with those which occur so abundantly in Peeblesshire, Berwickshire, Selkirkshire, Dumfriesshire, and Galloway. In Dumfriesshire I traced the coal field under the red sand-stone. In Lanarkshire the red sand-stone contains beds. VOL. VII. N° 1. F of basalt, porphyry, green-stone; and veins of basalt having sides of pitch-stone traverse the sand-stone strata. These veins, it may be remarked, are of the same nature with those discovered in the island of Lamlash, and agree with those discovered in Iceland by Sir George Mackenzie. III. Specific Gravity of Men. In the year 1757, Mr. Robertson published in the Philosophical Transactions a set of experiments on the specific gravity of men. He constructed a vessel, in which men might be immersed, and he determined the specific gravity by the rise of the water in the vessel. Ten trials were made in this way on ten labouring men belonging to the ordinary of Portsmouth yard. They were all thin, and varied in size from 6 feet 2 inches to 5 feet 3 inches. I am induced to republish the results here, because I see it inserted in a contemporary Journal, that no experiments on this subject have ever been made. I have added a column exhibiting the specific gravity of the men, reckoning sea-water 1.000. From this table we see that all the men were lighter than seawater, and that all, except one, were lighter than rain-water. The weight requisite to bring the lightest to the same specific gravity as rain-water would have been 28 lbs.; and to bring him to the specific gravity of sea-water very nearly 30 lbs would have been required; while the heaviest man was only 0.6 of a lb. lighter than sea-water. SIR, IV. Criopyrite. (To Dr. Thomson.) In consequence of some erroneous accounts which have made their way into the public papers, respecting a new engine of the power of twenty horses, said to be constructed under the direction of the inventor of the block machinery, it appears that the public, as well as your Dundee correspondent, are very anxious to gain some more faithful account of this wonderful machine, for which a patent has been secured by Mr. Collier: a specification of which may be seen in the Repertory of Arts for November last. That you may be impressed with a just idea of this new machine, now denominated a Criopyrite (or Fire Ram) I beg to send you an extract from a letter, which I received last week, from my friend Mr. Brunel (under whose directions I am carrying on the new works in this yard); in answer to a letter of mine about the criopyrite; speaking of which, he informs me, "that nothing is more preposterous than the account which has been published respecting this new engine; which it is stated, consumes no more than th part of the fuel required for a steam engine of the like power. It is true, that an attempt has been made with a view of obtaining all these advantages, which the Patentee anticipated as certain. Having been called upon to witness its action, and to give my aid in directing its power, I am able to assure you that the new engine, supposed to possess a power equal to twenty horses, has not yet, to my knowledge, moved without some external aid of two or three men, The account given out, is therefore a gross imposition; and as you have my sanction, I hope you will do all you can to correct it." The machine at present being in embryo, your correspondent's wish for a diagram and description, I am sorry to say, cannot now be complied with. If your correspondent will refer to any, or all of the following publications, he will find an account, and several tables relative to the elasticity and expansive force of steam, of different degrees of temperature. Gregory's Mechanics, vol. ii. pp. 55, 396, &c.: Brewster's Ferguson, vol. ii. p. 408: Buchanan on Fuel, p. 147, &c. : Mr. Dalton's table of the force of vapour, of each degree of Fahrenheit, in 5th vol. of Memoirs of Manchester Society; since republished in 6th vol. of Nicholson's Journal: Article Steam in Encyclopædia Britannica, &c. &c. Ás to the incrustation on the inside of boilers, I imagine that the surest way of preventing it is by using none but water of the purest quality: but unfortunately that cannot always be obtained. Having been told, that oyster-shells suspended in the boiler would prevent all incrustation, I lately tried the experiment. The result was, that upon examining the boiler at the end of a month, there was found no difference of incrustation, either upon the inside, the stone floats, or upon the shells. Chatham, Dec. 12, 1815. I remain, Sir, your obedient servant, H.T. ELLICOMBE. V. Letter from Dr.Rees respecting Mr. Henry's Experiments on SIR, Bleaching. (To Dr. Thomson.) Dec. 1815. Accustomed to the perusal of your publication, I observed in the 36th number, not without some degree of surprise, a letter addressed to me several years ago, and signed WILLIAM HENRY. If the writer of that letter had condescended to direct his attention to the article OXYMURIATIC ACID, in the Cyclopædia, he would have found ample satisfaction on the subject of his correspondence. I shall content myself with referring him and the public to that article, without any further remark. I remain, Sir, with great respect, your obedient Servant, VI. New Method of preserving Meat. A. REES. M. Salmon Mauget, a French gentleman at present in London, has invented a new method of preserving meat. He makes the joint of meat undergo a certain process, which he conceals. This prevents putrefaction from taking place, after which the piece of meat may be hung up in the kitchen and gradually dried. VII. Gunpowder. A new mode of manufacturing gunpowder has been invented in France, we believe by M. Champy, who is at present in this country. The grains are spherical, of the size of swan-shot, well glazed, and composed of concentric coats. The advantages which it possesses over common gunpowder are that the manufacture of it is much cheaper, and that it burns at least six times more rapidly than common powder. A committee of the Institute was appointed by Louis XVIII. to examine this powder, before Bonaparte landed from Elba. They gave a favourable report concerning it. The mode of making this powder has not been made public. VIII. Accidents from Scating. Scarcely a winter passes over without one or more fatal accidents happening from scating in St. James's Park, when the sheet of water in the middle of it is covered with ice. When a person has the misfortune to fall into the water, by the breaking of the ice, it is hardly possible to give him any assistance. Whoever attempted it, would be almost sure to share his fate; so that in such cases, the unhappy young man is drowned, though surrounded by a crowd of friends and acquaintances, each anxious for his safety. It is rather surprising, that no precautions have been taken to prevent the fatal effects of falling through the ice in this place. If a small light boat were placed by the side of the water, it would be possible, by means of it, to save the life of the person who had fallen into the water. There is a still cheaper and simpler method which, I conceive, would be sufficient. If a rope were at hand, long enough to extend across the sheet of water, with a weight attached to it, it might be thrown to the person who had fallen through the ice; he would of course catch hold of it, and might be drawn out. Two or three such ropes should be placed at convenient distances along the lake, so as always to have one near at hand, at what place soéver the scater falls in. IX. Dew. The phenomena of dew have been explained in so satisfactory a |