On Preparing some Colored Fires (Bengal Lights) used in Pyrotechny
SCIENTIFIC AMERICAN SUPPLEMENT, No. 49. 781 such a black line as this would, if placed at ten tance, subtend an angle of t" very nearly (one ninth of a second). inches dis-' I PLASMA TUBES OF THE HUMAN SKIN. AXEL KEy and GUSTAVE RETZIUS give a brief statement of the results of their researches on the plasma passages of the skin, especially of the superior extremities. A more complete account of their studies will be found in their work, now Viewed with a power of 18, its angle would be 2
... e would be 2 seconds. With a power of 540 the visual angle would be raised to 60" or l' 1 (more accurately 9.2 second, which would give 2175 instead of 18, and then the power would be 650 instead of 540). If therefore the lines on Nobert's plate, 112,000 to the inch � ere really simple black lines, they ought, with ordinary sight, to be easily distinguishable with a magnifying power of about 600 diameters, and this would make a visual angle thirty times greater than Mr. Broun's result above stated. B � t the � e lines in ge � eral are grooves ploughed in glass of a prISmatIC, round, or Irregular section; and since they can ?nly be s . een with extremely oblique illumination (looking as It were Sideways) by means of the very wide-angled objective generally found necessary, it is probable that the available shadow may be much less than the supposed breadth of the line, and quite indeterminable. In cutting' lines on glass with a diamond, I have been occa sionally much surprised with the beautiful little curls or ring lets cut cleanly out of the glass surface; but this only hap pened when the diamond-holder was rotated into one particu lar position, and inclined at one particular angle. When, therefore, we are looking at such fine" Nobert" grooves in glass, we are somewhat in the dark as to what kind of object or shad ? w we are rea�ly ob � erving. For if different grooves be cut III glass, formmg differently shaped channels in sec tion, whether oval, circular, square, or triangular a remark able difference in appearance will be observed when viewed and illuminated obliquely with transmitted light. Nobert's grooves are, as it were, unknown ob jects, for we know not and never shall know the sectional shape of the hollow rul ings that compose them. UNDERGROUND TEMPERATURE. Report of Committee read in Matltematical and Physical Sci mce Section of the British Association, Gla�gow Meeting. PROFESSOR EVERETT submitted the report of the Under ground Temperature Committee. He began by explaining some of the thermometers which had been used for particular purposes, and afterwards said that the subject which had been under the consideration or the committee was the con vection of water in bores and of the means to prevent it. A great many experiments had been made, but they had been all rejected. They had, however, obtained some which were the best that had yet been got. 'fhere was an exceedingly deep bore at Sperenberg, about 20 miles from Berlin. It was 4052 Rhenish feet, or 4172 English feet deep, and the bore was almost entirely through rock salt, and full of water, and the temperature at the surface was 7.2 deg. Reamur; at 700 ft. the temperature was 17.2; and at 3390 ft., the deepest point at which reliable observations were obtained. the tem perature was 37.2, and that gave 1 deg. Fahr. to 50 Rhenish feet. These observations showed that there was a decided decrease of the rate of increase as they went deeper. The next thing the committee had directed their attention to was flooding, and in that the most careful observations had been made to ascertain the effect of convection, and whether flood ing was necessary. The first experiment· was made to ascer tain whether the water at the bottom of the bore had the normal temperature of the surrounding rock. because if the water at the bottom did not possess that qualification the water in other parts would not. The way in which it was tested was, that when the bore had gone to a certain depth an advance bore was made of smaller diameter; and into that advance bore a thermometer was let down, and the bore then plugged at the place where it communicated with the big bore. The thermometer on being taken out gave a tem perature of something more than 36 deg., and the same therm � mete :r: let down without the bore being plugged gave a readlDg 01 33 deg. Reamur. Another thermometer of a difierent construction gave readings similar to those of the other. The committee had under consideration the obtaining of a plug which would effectually separate the water of the bore below from that above, and at the same time be easy to let down and draw up. Great difficulty had beell experienced in reference to that point, and that would now be the aim of the committee to secure such an appliance in order to get cor rect observations. Additional experiments had been made at a place called Swinderby, near Scarle, Lincoln, 2000 ft. deep, which he understood was the deepest bore in the east of Eng land. At that depth the temperature was found to be 79 deg. Fahr., and deducting from that the temperature of the surface-50 deg.-gave a. difference of 29 deg. Another obs � r :v ation at 1950 ft. gave a temperature of 78 deg. In additIOn to these, Mr. Symons had taken observations in a well at Kentish Town for the purpose of determining whether at a given depth-of say 1000 ft.-there was any change of temperature, but as the wire by which the thermometer had been let down had increased in length to an average over the two years of about 5 ft., there was really no reliable result obtained. Favorable observations had also been taken at Angers, in the North of Frall-ce. ACTION OF SALICYLIC ACID ON THE BONES. AT the meeting of the Niederrheinische Gesellschaft in Bonn on December 6th, 1875, Prof. Koster reported the re sults of his experiments on the action of salicylic acid on the osseous system. Pieces of spongy bone become soft aR leather in a few days when placed in a half per cent solution of sali cylic acid, while compact bone tissue is very slowly softened. The enamel of the teeth is very slightly affected by it, but the dentine where it is exposed by caries is rapidly destroyed. Dentists have alreaay recognized the evil effects of salicylic acid on the teeth. The increased amount of the salts of lime in the urine soon after salicylic acid has been taken. shows that the acid deprives living as well as dead bone of its lime salts. TAPE-WORM IN MEAT. AN article taken from the Abeille Medicale points out the danger of eating meat in the half-raw condition, called by some persons "rare," as the ova of the tape-worm are only killed by thorough cooking. Those whose tastes lead them to select meat in this condition are recommended to eat the flesh of the horse, which is less infected by the Trenia than the ox, sheep, or pig. passing through the press, "On the Anatomy of the Nerv ous System and the Connective Tissue." They mention the fact that, besides the true efierent lymphatic vessels, they have discovered in the skin an extended system of large plasma passages communicating with the lymphatic vessels mentioned, and resembling those which they have mentioned and drawn in the last fasciculus of their work, as existing in the mucous membrane of the nose. In the deepest parts of the skin, the plasma passages around the constituent parts (sweat-glands, hair-bulbs, etc.) are relatively large and wide· in the external portions they become more slender but abun� dant, and they form a fine net-work in the papilJre. They are � ot limited by the epidermis, however, but cross the papillre III many places and penetrate into the rete Malpighii. Our I a ? th ?.r s have, in fact, succeeded in injecting in the rete Mal plghn a fine net-work of plasma tubes with compact meshes ":hic� fill the intervals between the various cellules in every directIOn as far as the corneous layer. The intercellular in jectio � is arrf'sted externally by the latter cell layer; but there IS a system of passages at the surface of the Rkin which are so disposed that the injection penetrates the excretory ducts of the sudoriparous glands. With regard to the plasma passages of the rete Malpighii, our authors remark that M. Bi � ozero endeavored, sev t;. ral years ago, to prove that the splDes of the cells of the rete do not cross each other like the teeth of two wheel s, but that these" stachels and riffs" from adjacent cells hang tOllether by their points, leaving BDlall, spaces and passages between them. It is quite evident that it is these intervals which K. & R. have injected in the rete Malpighii, and which communicate with the plasma tubes of the dermis itself.-N ordiskt Med. Arkiv. DEAFNESS AS AN INTRACRANIAl. DISEASE. AT the recent meeting in Philadelphia of the Conference of Principals of Deaf-mute Institutions, Dr. Turnbull of Phila delphia, was invited to speak, and entertained the Conference with illustrations of the external and internal ear. He be lieved that deafness (excluding cases manifestly due to dis ease of the apparatus of hearing) is a rare complication of in tracranial disease. It is much less common than diseas� of the optic nerve, extending to the brain substance. One case he had recorded of abscess and tumor in the cerebellum with deafness of one ear. Dr. Jackson, of London, had recorded a tumor of the left cerebral hemisphere, where there was deaf ness of both ears. These facts go to prove that the brain of the deaf and dumb is as capable of receiving and retaining any amount of intel lectual knowledge as tllat of his hearin.,. brother or sister provided it is made available to him by the" eye,not by the ear: AT a lat� meeting of the Berlin Medical Society, Prof. Hen noch detaJled the histories of several cases of this affection occurring among children, which had come nnder his observa tion. The symvtoms were alarming dyspnrea, with pallor of the face and lividity of the lips, coldness of the extremities, small and t; xtr � mely frequent pulse, superficial, and very fre quent respiratIOn, and great mental apathy. The affection apparently depended upon disturbance of the digestive func tions. Tllere were in all of the cases BOme tumidity and tenderness in the epigastrium; but in spite of the threatenin.,. s � mptom8, not the least indication of cardiac or pulmonary disease could be found, on repeated and careful examinations. In one case, that of II; child of nine months old, in whom there had been constipation and vomiting, great relief was afforded by the application of numerous dry cups to the chest, and recovery from the attack coincided with the eruption of an incisor tooth. The other patients were children of nine years, three months, and two years, respectively, and all were relieved by the action of an emetic or cathartic. Prof. H., alt� � ugh sceptical at first, ultimately came to agree with the opmlOn expressed by Traube, who saw the first case in con sultation ; namely, that the disturbance in the stomach excited a reflex vaso-motor spasm in the small arteries, whence fol low � d . the coldness of the extre � ities, imperceptible pulse, stasIs III the venous system and right heart, cyanosis, accu mulation of carbonic acid in the blood, and dyspnrea. He therefore assigns the name asthma dyspepticum to the affec tion.-Berl. klin. Woch. SUSPENSION IN SPINAL CURVATURES. AT the recent meeting of the American Medical Association , Dr. Benjamin Lee , of Philadelphia, introduced a little girl, twelve years of age, illustrating the safety and feasibility of susvension in the treatment of spinal curvatures. '1'he appa ratus shown was a strong frame-work, from the middle of which was suspended his" spinal swing," being a rope pass ing over a pulley, carrying at one end a steel bow, to which are attached straps, to support the chin and occiput, and at the other wooden ovals to serve as handles. The head straps being so adjusted as to make equal traction on the chin and occiput in the line of the spinal axis, the patient, taking hold of the handles, drew down upon the rope until her feet were l!f � ed from the floor, and she swung freely, half the weight bemg supported by the neck, and half bl. the arms. She then drew herself up hand over hand untll her head nearlv touched the pulley, and then slowly let herself down again. A NEW ADHESIVE PLASTER. A MIXTURE of twenty parts of mucilage and one part of glycerine constitutes an excellent shining and supple plaster far cheaper tban the resin and diachylon, and lasting mor� than a year without deterioration. Three or four layers of the mixture require to be spread over each other on the linen or other stuff. allowing sufficient intervals for the successive layers to dry. A VENETIAN surgeon, Dr. Minich, has published a brochure on the antiseptic cure of wounds, in which he advocates .the employment of sulphate of soda in dressing of wounds (and al � o agai � st erysipelas), in preference to phenic and salicylic aCId. It IS much cheaper, and not attended by the inconveni ences of these acids. He uses one part of sulphate in nine ,parts of water, adding one part of glycerine. Dr. Minich shows that happy results have been obtained by this method in Venice in a large number of cases.