Popular Science Monthly/Volume 3/October 1873/Miscellany
Utilization of Waste Coal.—The English Mechanic gives an historical sketch of the various processes suggested for the utilization of the waste of coal-mines. From this account it would appear that so early as the close of the sixteenth century the waste of small coal attracted notice. About the year 1594 one Sir Hugh Piatt proposed a mixture of coal-dust and loam, together with such combustible materials as sawdust and tanners' bark: the loam being the cement which was to hold the other ingredients together. But Sir Hugh's suggestions did not receive much attention in those early times, when coal was but little used, wood being the staple fuel of England.
It was only at the beginning of the present century that this question began to receive serious attention. A patent was then granted for a mixture of refuse coal with charcoal, wood, breeze, tan, peat, sawdust, cork-cuttings, and other inflammable ingredients. A capital objection to such a scheme is its expense. The product would necessarily cost about as much per ton as good coal, without being at all as serviceable. The next attempt was the production of "gaseous coke." Here the object was to convert small coal, by the addition of coal-tar, either pure, or mixed with naphtha, into a well-mixed mass. It was then to be put into an oven and coked; afterward it was to be broken into suitable blocks for use. There were several modifications of this process, but as they all more or less involved the previous manufacture of their most essential ingredient, coal-tar, the anticipations of the projectors were not realized.
In 1823 a step was taken in the right direction by the combination of bituminous and anthracite coals, and converting them, by partial carbonization in an oven, into a kind of soft coke. In 1845 Frederick Ransome introduced a plan for cementing together small coal by means of a solution of silica dissolved in caustic soda, the small refuse coal so treated to be then compressed into blocks suitable for use. In 1849 Henry Bessemer proposed simply to heat small coal sufficient to soften it, and thus render it capable of being easily pressed into moulds and formed into solid blocks. The coal, according to this plan, might be softened either by the action of steam or in suitable ovens. Coal alone was used, no extraneous matter of any kind being employed. In 1856 F. Ransome brought forward one of the best plans yet offered. He placed the small coal in suitable moulds, which were then passed into an oven, and there heated just sufficiently to cause the mass to agglomerate.
Though the writer in the Mechanic commends highly the Ransome and the Bessemer plans, it is clear that they do not fully solve the problem, for inventors are still busy on both sides of the Atlantic devising other and better methods. Perhaps, however, the successful working of the Cranston "Automatic Reverberatory Furnace," which is adapted for the consumption of powdered coal, will cause such a demand for small coal as will leave these utilizing processes without material to work on.
Quatrefages on Human Crania.—Quatrefages is engaged on a work entitled "Crania of the Human Races," and recently laid before the Paris Academy of Sciences a synopsis of the results which he there proposes to establish. The materials he has at hand for this investigation are abundant—no less than 4,000 skulls; and he acknowledges the valuable assistance rendered to him by the most eminent savants both of France and of the rest of Europe. He holds that the fossil races are not extinct, but that, on the contrary, they have yet living representatives. He regards the skull discovered in 1*700 at Caustadt, near Stuttgart, as the type of the most ancient human race of which we have any knowledge. This skull is dolichocephalous—that is, having a length greater than its breadth. With the Canstadt skull he classes those of Enghisheim, Brux, Neanderthal, La Denise, Staengenaes, Olmo, and Clichy—the last-named three being the skulls of females. Among the representatives, in historical times, of the dolichocephalous race, M. Quatrefages reckons Kay Lykke, a Danish statesman of the seventeenth century, whose skull is portrayed in the forthcoming work; Saint Mansuy, Bishop of Toul in the fourth century, whose skull is also figured; and Robert Bruce. Whether the cranium is long or short—dolichocephalous or brachycephalous—is a question which has nothing to do with the intellectual status of the man, according to M. Quatrefages.
Heart-Disease and Overwork.—The early break-down of health observed among Cornish miners, and commonly regarded as an affection of the lungs—"miners' phthisis"—is declared, by competent authority, to proceed rather from disturbed action of the heart; and this, according to Dr. Houghton, the distinguished Dublin physiologist, is caused by the great and sudden strain put upon the system by the ascent from the pits, at a time when the body is not sufficiently fortified with food. In his valuable address on the "Relation of Food to Work," Dr. Houghton says: "The labor of the miner is peculiar, and his food appears to me badly suited to meet its requirements. At the close of a hard day's toil the weary miner has to climb, by vertical ladders, through a height of from 600 to 1,200 feet, before he can reach his cottage, where he naturally looks for his food and sleep. This climbing of the ladders is performed hastily, almost as a gymnastic feat, and throws a heavy strain (amounting to from one-eighth to one-quarter of the whole day's work) upon the muscles of the tired miner, during the half-hour or hour that concludes his daily toil. A flesh-fed man (as a red Indian) would run up the ladders like a cat, using the stores of force already in reserve in his blood; but the Cornish miner, who is fed chiefly upon dough and fat, finds himself greatly distressed by the climbing of the ladders—more so, indeed, than by the slower labor of quarrying in the mine. His heart, over-stimulated by the rapid exertion of muscular work, beats more and more quickly in its efforts to oxidate the blood in the lungs, and so supply the force required. Local congestion of the lung itself frequently follows, and lays the foundation for the affection so graphically though sadly described by the miner at forty years of age, who tells you that his other works are very good, but that he is 'beginning to leak in the valves' Were I a Cornish miner, and able to afford the luxury, I should train myself for the 'ladder-feat' by dining on half a pound of rare beefsteak and a glass of ale from one to two hours before commencing the ascent."
Poisonous Volcanic Gases.—During a volcanic eruption on the little island of San Jorge, one of the Azores, in the year 1808, vaporous clouds were seen to roll down the sides of the mountain, and to move along the valley. Wherever they passed, plants and animals wilted and perished instantaneously. From this asphyxiating action, as also from their downward movement on the mountain-side and toward the sea, we may conclude that they consisted chiefly of some dense, deleterious gas, most probably carbonic acid. Their opacity is to be attributed to the presence of watery vapor, and their reddish color to the presence of fine volcanic dust. Finally, their injurious action on plants was doubtless owing to the presence of chlorhydric and sulphurous acid. Similar phenomena have been observed on occasion of other volcanic outbreaks, but nowhere so marked as in the case of San Jorge. In 1866, for instance, the volcano of Santorin emitted smoke charged with acid, which produced on plants effects similar to those observed at San Jorge in 1808.
A writer in the Revue Scientifique is of the opinion that the facts above stated give the solution of some of the problems raised by the exhumations at Pompeii. The strange posture of skeletons found in the streets of that town is very difficult to account for, if we insist on finding analogies with phenomena observed in modern eruptions of Vesuvius. A shower of ashes, however heavy, however charged with humidity, could never have thrown down and choked a strong man like the one who met his death while making his escape, in company with his two daughters, along one of the public roads. They must have inhaled a poisonous gas of some kind, which caused them to perish in fearful agony. This gas would not lie in a layer of equal thickness: in some places it might have a greater depth than in others. Hence, while some of the inhabitants would perish, the remainder would escape.
It is very probable that the eruption in the year 79 was accompanied with local emissions of carbonic acid, springing from points remote from the crater. In all volcanic regions, says the author, there are localities where, even when the volcano is inactive, carbonic acid exists in the atmosphere, in quantities sufficient to produce asphyxia: and the neighborhood of Vesuvius is particularly noted for the number of such localities. During an eruption, the amount of the gas given out is usually increased, and wells, ditches, quarries, etc., are filled with carbonic acid. It is sometimes dangerous to enter cavities in the rocks on the coast when a fresh breeze does not keep them free of the poisonous gas. In 1861 Ste.-Claire Deville came near meeting his death by entering one of these cavities for a few moments. The following week he and the author barely escaped being asphyxiated in the bed of a great quarry, which they had previously visited many a time with impunity.
A Relic of Ancient Etrurian Art.—An antiquarian discovery of very considerable interest was recently made at Cervetri, Italy, being a terra-cotta sarcophagus of native Etruscan production. The ancient Etrurians were noted for the honor they bestowed upon their dead, and their custom of paying homage to ancestors by placing their effigies upon their tombs seems to have been peculiar to themselves, and unknown among the Greeks. The recently-discovered sarcophagus is now in the British Museum. It measures internally four feet ten inches in length, and two feet in width. The floor is hollowed out, or rather marked by a raised border, which takes the form of a human figure. It rests upon four claw feet projecting beyond the angles, and terminating above in the head and breasts of a winged siren. The lid of the sarcophagus represents an upholstered couch upon which recline two human figures, male and female. There are inscriptions on the four sides of the couch. The panel at the foot has the figures of two warriors in panoply, and the front panel exhibits the same pair of warriors engaged in mortal combat. Several accessory figures are also to be seen. On the panel at the head of the couch are represented four sitting figures in opposing pairs, plunged in deep sorrow. The monument has no counterpart among those of its kind hitherto discovered, the only one at all resembling it being that of the Campana Collection in the Louvre. The latter is, however, of a much more recent date than the former, nor is it adorned with either reliefs or inscriptions. The Cervetri sarcophagus probably dates from the period of Etruscan ascendency in Italy.
Audible and Inaudible Sounds.—The phenomenon of color-blindness is a familiar fact; but an analogous phenomenon, what might be called pitch-deafness, though not uncommon, is not so generally known. By pitch-deafness is meant insensibility to certain sound-vibrations. Prof. Donaldson, of the University of Edinburgh, used to illustrate the different grades of sensibility to sound by a very simple experiment, namely, by sounding a set of small organ-pipes of great acuteness of tone. The gravest note would be sounded first, and this would be heard by the entire class. Soon some one would remark, "There, 'tis silent," whereas all the rest, perhaps, would distinctly hear the shrill piping continued. As the tone rose, one after another of the students would lose sensation of the acute sounds, until finally they became inaudible to all.
There is reason for supposing that persons whose ear is sensitive to very acute sounds are least able to hear very grave notes, and vice versa. Probably the hearing capacity of the human ear ranges over no more than 12 octaves. The gravest note audible to the human ear is supposed to represent about 15 vibrations per second, and the sharpest 48,000 per second.
The auditory range of animals is doubtless very different from that of man; they hear sounds which are insensible to us, and vice versa. Many persons are insensible to the scream of the bat—it is too acute. But to the bat itself that sound must be in all cases perfectly sensible. If, then, we suppose the bat to have an auditory range of 12 octaves, and its scream or cry to stand midway in that range, the animal would hear tones some six octaves higher than those audible to the human ear—two and a half million vibrations per second.
Scoresby and other arctic voyagers and whale-hunters have observed that whales have some means of communicating with one another at great distances. It is probable that the animals bellow in a tone too grave for the human ear, but quite within the range of the cetacean ear.
The Motions of the Heart.—According to the generally-accepted teachings of physiologists, the heart rests after each pulsation; that is, each complete contraction during which the auricles are emptied into the ventricles, and the ventricles into the vessels, is followed by a moment's repose, when the organ is entirely at rest. Dr. J. Bell Pettigrew, in his recently-published lectures on the "Physiology of the Circulation," takes a different view, affirming that the normal action of the heart is a continuous one, and that as a whole it never ceases to act until it comes to a final stop. He says: "When the heart is beating normally, one or other part of it is always moving. When the veins cease to close, and the auricles to open, the auricles begin to close and the ventricles to open; and so on in endless succession. In order to admit of these changes, the auriculo-ventricular valves, as has been stated, rise and fall like the diaphragm in respiration; the valves protruding, now into the auricular cavities, now into the ventricular ones. There is in reality no pause in the heart's action. The one movement glides into the other as a snake glides into the grass. All that the eye can detect is a quickening of the gliding movements, at stated and very short intervals. A careful examination of the sounds of the heart shows that the sounds, like the movements, glide into each other. There is no actual cessation of sound when the heart is in action. There are periods when the sounds are very faint, and when only a sharp or an educated ear can detect them, and there are other periods when the sounds are so distinct that even a dull person must hear; but the sounds—and this is the point to be attended to—merge into each other by slow or sudden transitions. It would be more accurate, when speaking of the movements and sounds of the heart, to say they are only faintly indicated at one time, and strongly emphasized at another, but that neither ever altogether ceases. If, however, the heart is acting more or less vigorously as a whole, the question which naturally presents itself is, How is the heart rested? There can be little doubt it rests, as it acts, viz., in parts. The centripetal and centrifugal wave-movements pass through the sarcous elements of the different portions of the heart very much as the wind passes through the leaves: its particles are stirred in rapid succession, but never at exactly the same instant; the heart is moving as a whole, but its particles are only moving at regular and stated intervals; the periods of repose, there is every reason to believe, greatly exceeding the periods of activity. The nourishment, life, and movements of the heart are, in this sense, synonymous."
Poisoning by Oxygen.—M. Paul Bert, whose observations upon the physiological effects of high atmospheric pressure we have already noted in the Monthly, communicates to the Paris Academy of Sciences the results of his observations on the toxic action of oxygen. Placing sparrows in oxygen under a pressure of 350 (that of the atmosphere being represented as 100), he found the birds seized with violent convulsions. The same result followed when sparrows were confined in common air under a pressure of 11 atmospheres. In oxygen, at 3½ atmospheres' pressure, or in air at 22 atmospheres, the convulsions were extremely violent and quickly fatal. The symptoms in the latter case were these: Convulsions set in after four or five minutes: in moving about, the bird hobbles on its feet, as though walking on hot coals. It then flutters its wings, falls on its back, and spins about, the claws doubled up. Death supervenes after a few such spasms.
The toxic dose of oxygen for a dog was found to require, for convulsions, a pressure of 350 in oxygen; and a pressure of 500 is fatal. The amount of oxygen in the arterial blood of a dog in convulsions was found to be considerably less than twice the normal quantity. Hence the author's startling conclusion, that oxygen is the most fearful poison known.
Taking a dog in full convulsion out of the receiver, M. Bert found the paws rigid, the body bent backward in the shape of an arch, the eyes protruding, pupil dilated, jaws clinched. Soon there is relaxation, followed by another crisis, combining the symptoms of strychnine-poisoning and of lockjaw. The convulsionary periods, at first recurring every five or six minutes, become gradually less violent and less frequent.
The author sums up his conclusions as follows: 1. Oxygen behaves like a rapidly-fatal poison, when its amount in the arterial blood is about 35 cubic centimetres per cent, of the liquid; 2. The poisoning is characterized by convulsions which represent, according to the intensity of the symptoms, the various types of tetanus, epilepsy, poisoning by phrenic acid and strychnine, etc.; 3. These symptoms, which are allayed by chloroform, are due to an exaggeration of the excito-motor power of the spinal cord; 4. They are accompanied by a considerable and constant diminution of the internal temperature of the animal.
Infant Mortality.—During the year 1868, 23,198 children under one year of age, died by convulsions in England, the number of births being 786,858—one in 34. In the same year the births in Scotland were 115,514, and only 312 infants under one year
On comparing these statistics with those of the last United States census, it will be seen that the chances of life for infants in their first year are far more favorable in this country than in England, though not so favorable as in Scotland. In the year ending May 31, 18*70, there were born in the United States 1,100,475 children. Of these there died, during the same year 4.863 by convulsions, and 1,534 by diarrhoea, or one in 236 from the former cause, and one in 724 from the latter. In England the deaths from diarrhoea amounted to 138 in 100,000 infants, and in Scotland to 66 in the same number. It will be seen, on computation, that the proportion of deaths from this cause are by a very small fraction less in the United States than in Scotland. But now are we to attribute these very creditable results to our more rational system of rearing children, or to the better social condition of the population here?
Snakes swallowing their Young.—The question, "Do snakes swallow their young?" that is, give them shelter in the maternal stomach when danger threatens, was discussed in a paper presented to the American Association by G. Brown Goode. The author some time since asked, through the public press, for testimony bearing on this subject, and he now comes forward with what appears to be perfectly satisfactory evidence in favor of the affirmative side. He has the testimony of fifty-six witnesses who saw the young enter the parent's mouth. Of these fifty-six, nineteen testify that they heard the parent snake warning her young of danger by a loud whistle. Two of the witnesses waited to see the young emerge again from their refuge, after the danger was past; and one of them went again and again to the snake's haunt, observing the same act on several successive days. Four saw the young rush out when the parent was struck; eighteen saw the young shaken out by dogs, or escaping from the mouth of their dead parent. These testimonies are confirmed by the observations of scientific men, such as Prof. Smith, of Yale College, Dr. Palmer, of the Smithsonian Institution, and others.