over and over again with the same tone and modulation of voice, a c' pipe of 256 double vibrations be strongly sounded; it appears as if two persons were reading together, one with a grave voice (formed by a combination of all the reader's real vocal sounds below c' in pitch), the other with a high-pitched voice, generally squeaky and nasal, and of course disagreeable. This obliteration of higher by lower sounds, the author believes, has an important bearing on orchestral music. In the first place it will require the conductor of the orches tra to change his position to one nearer the midst of the audience. In the second, it will require a study of the relative intensity of the components of typical musical tones used in orchestral performances, so that those can be heard which the composer desires should be.-4 D, November, 1876, 329.

NEW METALLIC PYROMETER,

Though much improved of late years, pyrometers are not exactly all that could be desired. Hence the frequent appearance of new forms of that most desirable instrument. M. A. F. Huet, of Paris, has recently obtained provisional protection for an invention of this kind, being an instrument consisting of a rod of copper contained in a porcelain tube. The characteristic feature of the invention is said to be the particular arrangement of the bar of copper, which with its porcelain tube is inclosed in the wall of a furnace, into which the porcelain tube penetrates a suitable distance. Outside the furnace the tube terminates in a foot or support screwed down upon a plate. Inside the tube is the rod of copper, which is fixed at the inner end by means of a screw-nut at the end of the tube. This rod is prolonged outside the furnace, and terminates in a fork which embraces the vertical branch of a lever. To avoid all contact of the porcelain socket with the copper rod, an asbestus washer is arranged on each side of the screw-nut which fixes the rod and the socket at one end. To render the action of the heat from the furnace more direct upon the copper rod, small holes are pierced in the part of the socket which is inside the furnace. The lever is free to oscillate on an axis. The extremity of the other branch of the same lever is fastened by a joint to the top of a rod which carries a regulating screw-nut, this being terminated at the bottom by a piston destined to press

upon liquid in a cistern in connection with a glass thermometer or siphon tube up which the liquid passes, and indicates upon a gauge the heat of the furnace. The defect of this arrangement, apparently, lies in the fact that, after being submitted to high temperatures, the rod of copper would take up a permanent elongation, and refuse to expand or contract to the desired extent or with the desired accuracy.-18 A,

553.

CONDUCTION OF HEAT IN GASES.

The question of the conducting power of gases for heat is one which has received a large share of the attention of eminent physicists. The most recent of these researches is that of Winkelmann, who employed for measurement of the heatconduction the same method which other observers have used; i. e., he measured the rate of cooling of a thermometric body within a vessel filled with the gas to be examined. The difficulty of these experiments lies in the fact that the cooling is caused not only by the conduction of the gas which surrounds the cooling body, but also by the currents which are set up in the gas, and especially by radiation through it. Winkelmann addressed himself particularly to the task of eliminating these currents and the radiation. He effected this in one case by varying the pressure of the gas between 760 millimeters and one, since with diminishing pressure the action of the gas currents becomes less. In another experiment, he employed various apparatuses in which the cooling body within was always of the same dimensions and the same material, while the outer envelope was varied in size. The value of the radiation was then in all apparatuses the same, while the conduction varied with the size of the outer vessel, and so furnished data by means of which the radiation could be calculated and eliminated. The results obtained with several of the more common gases are as follows:

The fullest series of experiments were made with air and hydrogen, and the numbers obtained for these gases showed that in air, down to a pressure of one millimeter, the conduction of heat is independent of the pressure. Hydrogen, on the other hand, showed a quite divergent and hitherto unexplained behavior with reference to pressure, the changes of the currents in this gas with different pressures by no means affording an explanation of the observed differences in the ve locity of cooling. In proof of this, for example, he states that whereas with a lowering of the pressure from 750 millimeters to 91.4 millimeters, there was a lowering of the value for the velocity of cooling of only 1.4 per cent. ; yet that on further diminishing the pressure to 4.7 millimeters, there was a further decrease of 11 per cent., the decrease continuing when the pressure was still further lowered to 1.92 millimeters. Whether the circumstances operating in this case were accidental, or whether these anomalies are due to the properties of the gas itself, can be decided only by further and more exact researches. Besides the above question of simple heat-conduction in gases, Winkelmann also undertook to determine the relation in which heat-conduction stands to the temperature employed. In this investigation he had to employ new apparatus made of glass. He was also obliged to effect the separation of the conduction from the radiation on a different principle from that used in the former measureThe observations were so arranged that first the time of cooling from 18° to 8° was determined, and then from 118° to 108°. With three apparatuses, very different in their dimensions, the author obtained the temperature coefficients 1.3661, 1.3429, 1.3644, referring to the temperatures 7.4° to 7.6°, and 107.7° to 109°. That is to say, if the heat-conduction at the lower temperature be put equal to one, then at the higher temperature it has the value just given. Besides air and hydrogen, carbonic acid was also examined in these researches. If the latter changes its heatconduction with the temperature in the same way as air and hydrogen, it is obvious, by combination of the values of hy drogen and carbonic acid, that the same relative numbers should be obtained as those given by hydrogen and air. The values so obtained, however, are altogether smaller, whence it appears that the conduction of carbonic acid is not de

ments.

pendent on temperature in quite the same way as that of hydrogen, but increases more quickly with the temperature. The value of these results in the theory of gases is very considerable.-Poggendorff's Annalen, 1876.

CREMATION IN FRANCE.

In December, 1875, a committee was appointed by the Council of Health and Hygiene of the Department of the Seine to consider and report upon the subject of cremation. This committee consisted of MM. Baube, Bouchardat, Boussingault, and Troost, the latter being the rapporteur. The report of this committee, after noting that the letter of the Prefect of Police did not suggest any special direction which the investigation should take, states that they confined their attention to the following points: (1) The possibility of effecting the incineration of bodies without production of smell or smoke or deleterious gases; (2) the advantages such incineration might offer as regards salubrity; and (3) the inconveniences it would present as regards criminal investigations. They did not have to concern themselves with the propriety of respecting the celebration of religious ceremonies; that propriety having been recognized by the municipal council, and by the administrative committee which fixed. the programme of the competition for the invention of the best process for incinerating dead bodies, or of any other system giving a like result. It is, further, well understood, they say, that incineration would be in no wise obligatory, but simply optional, under conditions to be determined by a special law. With reference to the first question examined by the committee, the report is very brief. They do not doubt that by having recourse to gas furnaces, like those used in metallurgy, a rapid incineration could be had. It would be possible also to obtain, without any admixture of foreign matters, the ashes of bodies subjected to cremation. No fetid odor or smoke would be evolved, these furnaces being essentially smoke-consuming. Thus there would be no danger to public health to be feared. The conditions of the municipal council's programme might therefore be easily fulfilled, except perhaps that of economy, it being evident that until these furnaces can be occupied continuously they can not be operated economically. On the second point exam

ined, the committee say that in their opinion cremation would present advantages over the mode of inhumation in a common graveyard, where insufficient space is reserved for each body. Fetid emanations and the alteration of subterranean waters may, in fact, result where the earth is saturated with organic matter in decomposition, and the air can not penetrate in sufficient quantity to produce a complete combustion. The most serious inconveniences of our present cemeteries, however, disappear where only a limited number of bodies sufficiently separated are contained in properly per meable strata. The land thus used might be returned to agriculture, after having been closed for a number of years; for the bodies buried in permeable soil are subjected to a sort of slow and indirect combustion, which does not present any inconvenience so long as the intermediate and dangerous products do not reach the surface of the ground. On the third point, the report asserts that inhumation presents guarantees for society which are not found in cremation, if the question be considered with reference to the investiga tion and determination of poisons, the existence of which is often not suspected till long after death. Dividing poisons into two classes, those which cremation would cause to disappear and those which it would not destroy completely, the committee say that in the case of the former class, in which rank all toxical substances of organic origin, and also arsenic, phosphorus, and corrosive sublimate-the very poisons, by the way, most commonly employed-cremation would obliterate all traces of the crime, would thus insure immunity from punishment, and so encourage the repetition of crime. In the case of the second class of poisons, which includes copper and lead, for example, while the metal might be found in the ashes, yet the persons interested would, it is clear, always have the opportunity of dispersing those ashes, or of replacing them with others; so that, in this event, the traces of crime would also be easily obliterated. For these reasons criminals might find in cremation a security which they have not in the present process of inhumation, and which it is important not to afford them, for it would be a source of more serious danger to the population than the insalubrity of cemeteries. The objections thus raised against cremation, however, would disappear if the law required that before any