Chambers's Journal of Popular Literature, Science, and Art, No. 726

The statements thus set forth are illustrated by diagrams which shew the position of the vessel after reversal of the screw, and the position after steaming ahead. The latter shews that collision would be entirely avoided.

We frequently read that in future sea-fights the ram will be relied on for running down enemy's ships and sending them to the bottom. But where is the captain at the present day who has had experience of ramming, and of other evolutions which will be required in a fleet of steam ironclads under quite new conditions? Soldiers can go into temporary camps and get experience in 'autumn manœuvres;' but sailors cannot have mock-actions and run down ships which cost half a million sterling, nor venture to try the eighty-ton-gun on their consorts. Hence there will be very much to learn in the first great naval battle.

Under these circumstances, Professor Reynolds recommends that small steam-launches should be built of wood, each representing the exact form of one of our large ships, and that with these all possible manœuvres should be carried out, and officers make themselves familiar with all the effects of the screw on the rudder, with all the conditions of steering, with all the evolutions requisite to bring about or to avoid a collision, and with the effects of ramming. If strongly built of wood, these little vessels would withstand an experimental blow from the ram.

The value of such experiments would be real, for it is now known that the behaviour of a small copy of a ship is exactly the same as that of the great ship, in proportion to the size. The waves set up by the launch bear the same relation to her size as the waves of the ship do to the ship. The recognition of this law marks an epoch in the progress of naval architecture. Given a model, Mr Froude 'can now predict with certainty the comparative and actual resistance of ships before they are constructed.'

The Report of the Committee for investigating the circulation of the underground waters in the New Red Sandstone and Permian formations of England, and the quantity and character of the water supplied to various towns and districts from these formations, conveys information interesting to everybody – for everybody drinks. At Liverpool there are wells sunk in the New Red Sandstone which yield more than seven million gallons daily; at Birkenhead the same; at Coventry, Birmingham, and Leamington four millions and a half; at Nottingham nearly four millions; and at Warrington and Stockport more than a million and a half gallons every day. The total makes up a large quantity; but it is nothing in comparison with the supply which the whole area of the New Red may be expected to furnish. This area, says the Report, is certainly not less than ten thousand square miles in extent in England and Wales, with an average rainfall of thirty inches, of which certainly never less than ten inches per annum percolates the ground, which would give an absorption of water amounting to no less than one hundred and forty-three millions three hundred and thirty-six thousand gallons per square mile per annum; which, on an available area of ten thousand square miles, gives an annual absorption of nearly a billion and a half of gallons in England and Wales. As if to heighten the effect of this good news, we are told the 'New Red Sandstone Rock constitutes one of the most effective filtering media known… It exerts a powerful oxidising influence on the dissolved organic matter, which percolates it to such an extent, that in the waters of certain deep wells, every trace of organic matters is converted into innocuous mineral compounds.' And again: 'Waters drawn from deep wells in the New Red Sandstone are almost invariably clear, sparkling, and palatable, and are among the best and most wholesome waters for domestic supply in Great Britain.' After reading this, may we not say that Undermere, about which no one will quarrel, is the lake whence great towns in the north should draw their water supply?

During the meeting of the British Association at Plymouth last August, the Mineralogical Society held their second annual gathering under the presidency of Mr Sorby, F.R.S., who in his address gave an account of a new method for determining the index of refraction of minerals, which can be readily employed in their identification. This seems a dry subject; but it is one likely to be valuable and interesting to mineralogists and chemists, and to lead to an entirely new branch of mineralogical study, and to the discovery of a new class of optical properties of crystals. For a proper understanding of the method, a knowledge of optics, of mathematics, and other branches of science would be necessary; but we may state generally that it is based on the fact, that if an object, when placed in focus for examination on the stage of a microscope, is covered with a plate of some highly refracting substance, the focal length is increased; in other words, the microscope must be raised a little farther from the object in order to restore the focus. The distance to which the microscope has been moved thus becomes a measure, which can be accurately determined on a scale to thousandths of an inch. By this measure, therefore, very minute differences of refraction can be determined, and the several minerals identified; and Mr Sorby, in conjunction with Professor Stokes, Sec. R.S., has arrived at certain definite conclusions, which, embodied in numerical tables, may ere long be consulted by all interested in the subject.

On this point Mr Sorby explained in his address: 'On applying this method to the study of various minerals, the difference is found to be very great. We can mostly at once see whether they give a single unifocal image or one or two bifocal images, and form a very good opinion respecting the intensity of the double refraction, and easily determine whether it is positive or negative… These facts combined furnish data so characteristic of the individual minerals, that it would usually be difficult to find two approximately similar… It has been said that in studying the microscopical structure of rocks it is often difficult to distinguish nepheline from apatite. But the index of nepheline is about 1.53, whereas that of apatite is 1.64, and such a considerable difference could easily be recognised in a section not less than one-fiftieth of an inch in thickness.'

The observations hitherto made prove that minerals may be ranged in classes according to their refracting power and their chemical composition. The fluorides are lowest in the scale, while quartz, corundum, the sulphides and arsenides, are among the highest. From these particulars it will be understood that researches into mineralogy have a prospect of becoming more and more interesting.

As we have a British Association for the Advancement of Science, so our neighbours across the Channel have a French Association. It met last August at Havre, and in a few of its fifteen sections manifested signs of activity. Among the meteorologists, diagrams were exhibited shewing clearly that the 'changes of pressure in the upper regions of the atmosphere are by no means similar to those at the surface of the earth; for when the pressure at the lower station decreases, it rises at the upper station, and the reverse; or when it is steady at the one, it rises or falls at the other.' A line of telegraph for meteorological purposes is now erected from Bagnères to the Pic du Midi, seventeen miles. The Pic is nine thousand feet high, and will be an interesting observing station, in constant communication with the lower regions. A proposition was made that the Transatlantic steam-ship companies should be requested to institute regular meteorological observations on board their vessels; and that the captive balloon of next year's Great Exhibition at Paris should be an observing station. Paris is chosen as the meeting-place of the Association for next year, and at the same time a free international meteorological congress will be held.

During recent years it has been said that the marshes and saltish depressions in the territory of Algiers and other parts of North Africa were once covered by the sea, and schemes have been announced for readmitting the sea by cutting channels from the Mediterranean. Mr Le Chatelier, a French chemist, says – the existence of the salts is not due to the drying up of a former sea, but to the masses of rock-salt which exist in the mountains. From these the salt is dissolved out by rain or by subterranean waters, and the saline solution percolates the soil to feed the artesian reservoirs which underlie the desert. These observations will require attention from geographers.

If any apology were required for a somewhat late notice of Dr Sayre's method of rectifying curvature of the spine, it would be found in the fact that among the arts the healing art holds an eminent place, and has special claims on every one's attention. Dr Sayre, an American, has this year visited England to make known his method of curing those malformations of the backbone under which many persons remain cripples for the whole of their life; and now that it is known, the wonder is that it was not thought of before. In carrying out the operation, the patient is lifted from the ground, and suspended by a support under the chin and back of the head: sometimes a support is placed under the armpits, and sometimes the arms are raised. In this position the weight of the pelvis acts on the crook in the spine, and pulls it straight; a bandage dipped in plaster of Paris is then bound round the body; a few iron splints are inserted in the bandage, and as the plaster dries, a mould is formed, which keeps the straightened bones in place. The suspension is now at an end; the patient is found to be an inch or two inches taller than before the operation, and can walk without limping. After a few days, the plaster-mould is cut up each side, to allow of removal for washing the body; but the two halves are quickly replaced and held in position by a bandage. In some instances six months' wearing of the plaster-mould effects a cure, and the patient enjoys an ease and activity never before experienced.

This method of cure contrasts favourably with the treatment which keeps the patient supine many weary months. As may be imagined, it succeeds better with children than with adults; but even adults have been cured. A case occurred at Cork, the patient being a woman aged twenty-two, and requiring a little mechanical pulling to assist in the straightening; but it was accomplished, and she walked out of the room two inches taller than she entered it.

Mr Hoppe-Seyler, a learned German, has published a paper on Differences of Chemical Structure and of Digestion among Animals, supported by numerous examples, which shew that according to the organism so is the power to form differences of tissue; and he sums up thus: 'Looking at the question broadly, we find that the chemical composition of the tissues and the chemical functions of the organs present undoubted relations to the stages of development, which shew themselves in the zoological system, as well as in the early stages of development of each individual higher organism. These relations deserve further notice and investigation, and are qualified in many respects to prevent and correct errors in the classification of animals. It is generally supposed that the study of development is a purely morphological science, but it also presents a large field for chemical research.' This concluding sentence is significant, and should have serious consideration.

Waste pyrites from the manufacture of sulphuric acid is, as regards hardness, a good material for roads when mixed with gravel; but chemically it is not good. In the neighbourhood of Nienburg, Hanover, where roads and paths were covered with waste pyrites, it was found that grass and corn ceased to grow; and a farmer on mixing well-water with warm milk, observed that the milk curdled. The explanation is, that the waste pyrites 'contained not only sulphide of iron and earthy constituents, but also sulphide of zinc, and that by the influence of the oxygen of the atmosphere and the presence of water, these sulphides were gradually converted into the corresponding sulphates;' and these, continually extracted by the rain-water, soaked into the soil, contaminated the wells, and produced other injurious effects.

The want of really efficient names to distinguish various kinds of manufactured iron has long been felt in the iron trade. The Philadelphia Exhibition gave rise to a Commission which, after discussion of the question, have recommended that all malleable compounds of iron similar to the substance called wrought-iron shall be called 'weld-iron;' that compounds similar to the product hitherto known as puddled steel, shall be called 'weld-steel;' that compounds which cannot be appreciably hardened when placed in water while red-hot shall be called 'ingot-iron;' and that compounds of this latter which from any cause are capable of being tempered, shall be called 'ingot-steel.'

By further exercise of his inventive abilities, Major Moncrieff has produced a hydro-pneumatic spring gun-carriage perfectly adapted for use in the field. A gun mounted on this carriage could be made ready for action within ten minutes after its arrival in the trenches.

The Science and Art Department have commenced the publication of a 'Universal Art Inventory, consisting of brief Notes of Fine and Ornamental Art executed before the year 1800 chiefly to be found in Europe.' This is a praiseworthy undertaking, for there are so many rarities of art which can never be seen by the multitude, which can never be moved from their place or purchased, that an inventory thereof with descriptive notes cannot fail to be of great utility. Nearly all the governments of Europe and many royal personages are co-operating in this work, which includes reproductions in possible instances. Some of these reproductions are well known to the frequenters of the South Kensington Museum; for example, the great mantel-piece from the Palais de Justice at Bruges; Trajan's Column from Rome; a Buddhist gateway from India, of the first century; a monument from Nuremberg, and other elaborate works. As a means of reference, this Inventory will be welcome to many a student, and as it necessarily will take many years to complete, there will be the pleasure of watching for fresh instalments of information. But all students should remember that 'the laws of design are as definite as those of language, with much the same questions as to order, relationship, construction or elegance; differing for dissimilar styles as for divers tongues. The pupil in design has similar obstacles to encounter with those of the schoolboy in his alphabet and grammar; the ability to use the pencil or the brush will no more produce an artist than the acquirement of the writing-master's art with Lindley Murray's rules will make a poet.'

Professor Justin Winsor, one of the American delegates to the conference of librarians held last month, points out with much earnestness that by the extension of libraries a great impetus may be given to national education, and an opening made at the same time for the employment of women. In America, pains have been taken to engage men and women in the work who are content to labour to attain the level of a far higher standard than the public at large have been usually willing to allow as the test of efficiency. 'We believe,' remarks the Professor, 'that libraries are in the highest sense public charities; that they are missionary enterprises; that it is to be supine if we are simply willing to let them do their unassisted work; that it is their business to see two books read instead of one, and good books instead of bad. To this end it has been urged that one of our principal universities shall have a course of bibliography and training in library economy.'

In reply to various correspondents, we beg to state that the information regarding the manufacture of vegetable isinglass in Rouen, which appeared under the head of A Few French Notes in No. 717 of this Journal, was taken from L'Armée Scientifique, a work compiled by the well-known French savant, M. L. Figuier. As there seems to be some difficulty in reconciling M. Figuier's statements with the present state of the process as carried on in France, we are making further inquiry, and hope to be able to give early and definite information.

A FEARFUL SWING

The 'Shaftmen' at our collieries are selected for their physical strength and pluck, in addition to the skill and practical knowledge required for their particular work. The incident we are about to relate will shew how severely the former of these qualifications may at times be tested.

The work of these men is confined to the shaft of the pit, and consists mainly in repairing the 'tubbing' or lining of the shaft, stopping leaks, or removing any obstructions interfering with the free passage of the cages up and down the pit. The coal-pit at N – has a double shaft, divided by a 'bratticing' or wooden partition. These divisions we will call A and B. Two cages (the vehicles of transport up and down the pit) ascend and descend alternately in shaft A. At a certain point the shaft is widened, to allow the cages to pass each other, and their simultaneous arrival at this point is insured by the arrangement of the wire-ropes on the winding-wheels over the pit-mouth. The oscillation of the cages is guarded against by wooden guiders running down each side of the shaft, which fit into grooves in the sides of the cage.

On one occasion during a very severe frost these guiders had become coated with ice, and thus their free passage in the grooves of the cages was interfered with. Before this obstruction was discovered, the engine having been set in motion, the downward cage, which fortunately was empty at the time, stuck fast in the shaft before arriving at the passing-point. The ascending cage, whose only occupant was a small boy returning to 'bank,' proceeding on its upward course, crashed into the downward cage in the narrow part of the shaft, where of course there was only a single passage. Though the shock was something terrific, the steel rope was not broken; as the engineman, whose responsible position entails the greatest presence of mind and watchfulness, had stopped the engine on the first indication of an unusual tremor in the rope. Yet such was the violence of the meeting, that both cages, though strongly constructed of iron, were bent and broken – in fact rendered useless – by being thus jammed together in a narrow space. The greatest anxiety was felt as to the fate of the boy, as it was seen that even if he had escaped with his life after such a severe crash, his rescue would be a work of great danger and difficulty.

We may imagine the horror of the poor little fellow while suspended in the shattered cage over a gulf some four hundred feet deep, both cages firmly wedged in the shaft, and the ropes rendered useless for any means of descent to the scene of the catastrophe. The readiest way of approach seemed to be by shaft B, the position of which we have indicated above. Down this then, a Shaftman, whom we will call Johnson, descended in a cage until he arrived at an opening in the brattice-work by which he could enter shaft A. He found himself (as he supposed) at a point a little above where the accident had occurred; and this conclusion he came to from seeing two ropes leading downwards, which he naturally took to be those by which the cages were suspended. Under this impression he formed the design of sliding down one of the ropes, with a view to liberating, if possible, the entangled cages and securing the safety of the unfortunate boy. The hardy fellow was soon gliding through the darkness on his brave and dangerous errand. He had descended about forty feet, when, to his horror and amazement, his course was suddenly checked by a bend in the rope; and the terrible discovery flashed upon him, that he was suspended in the loop of the slack rope, which here took a return course to the top of the downward cage!

It will be understood that when the descending cage stuck upon the runners, as the rope continued to unwind from the pulley it hung down in a loop, descending lower and lower, until the engine was stopped by the meeting of the cages. This loop or 'bight' was naturally mistaken by Johnson for the two ropes, and he did not discover until he found himself in the fearful situation described, that he had entered through the brattice into shaft A below instead of above where the cages were fixed. There he hung then, over a yawning abyss many fathoms deep – closed from above by the locked cages – all below looming dark and horrible.

None of course knew his danger; his hands were chilled by the freezing rope; his arms, already fully exercised, began to ache and stiffen with the strain and intense cold, added to the bewildering sense of hopeless peril. Good need there was then that pluck and endurance be found in the Shaftman! His square sturdy frame and unflinching spirit were now on their trial. Had his presence of mind gone or his nerve failed, he must have been paralysed with fear, lost his hold, and been dashed into an unrecognisable mass.

But self-preservation is a potent law, and working in such a spirit he framed a desperate plan for a struggle for life. The guiders running down the inside of the shaft are fastened on to cross-beams about six feet apart. Johnson hoped that if he could reach one of these, he might obtain a footing whereon to rest, and by their means clamber up to the opening in the brattice-work. How to reach them was the next question that flashed lightning-like through his brain. This he essayed to do by causing the rope to oscillate from side to side, hoping thus to bring himself within reach of one of the cross-beams. And now commenced a fearful swing. Gaining a lodgment with one knee in the loop, he set the rope swinging by the motion of his body, grasping out wildly with one hand each time he approached the side of the shaft. Once, twice, thrice! he felt the cold icy face of the 'tubbing,' but as yet nothing except slimy boards met his grasp, affording no more hold than the glassy side of an iceberg. At last he touched a cross-beam, to which his iron muscles, now fully roused to their work, held on like a vice. He soon found footing on the beam below, and then letting go the treacherous rope, rested in comparative security before beginning the perilous ascent. With incredible endurance of nerve and muscle he clambered upward alongside the guider, by the aid of the cross-beams, and by thrusting his hands through the crevices of the timber. In this manner he reached the opening into shaft B, where the cage in which he had descended was waiting. Chilled, cramped, and frozen, and barely able to give the signal, he was drawn to the pit-mouth prostrate and exhausted. The boy was rescued unhurt by a man being lowered to the top of the cages in shaft A. Johnson suffered no ill consequences, and though a hero above many known to fame, he still pursues his hardy task as a Shaftman; while beneath the homely exterior still lives the pluck and sinew of iron that did not fail him even in his Fearful Swing.

TO MY ROBIN REDBREAST

The following lines are taken from The Captive Chief, a Tale of Flodden Field, by James Thomson (H. H. Blair, Alnwick, 1871).

Now keenly blows the northern blast;Like winter hail the leaves fall fast,And my pet Robin's come at lastTo our old thorn;With warbling throat and eye upcastHe greets the morn;Like some true friend you come to cheer,When all around is dark and drear.And oh! what friend to me more dearThan your sweet sel'?Your mellow voice falls on my earLike some sweet spell.Oft at the gloaming's pensive hour,When clouds above me darkly lower,I've sought a seat in some lone bower,With heart opprest;You soothed me with your magic power,And calmed my breast.When Morning dons her sober grayTo usher in the coming day,And Phœbus shines with sickly rayOn all around,No warblers greet him from the sprayWith joyous sound.But you, sweet bird, unlike the throng,Salute him with a joyous song.When heavy rains and sleet prolongThe dreary day,You chant to him your evening songUpon the spray.No blackbird whistles in the grove,Where late in chorus sweet they strove;No warbler's tongue is heard to move,But all is sad;No cushat woos his amorous loveIn hazel glade.