The electrical resistance manifested relatively by certain fused salts is peculiar. The following communication contains the result of observations on time changes of resistances noticed during the cooling and resolidification of two typical groups of fused salts and also of molten glass.

The Indians, to whom the preparation of these heads is traced, are scattered over a wide tract of country on the eastern side of the Andes. They are known under the general designation Macao, the name of the region they inhabit—a designation which includes the Jivaros, Pastazas, Mendes, Tumbas, and more than twenty other tribes. Early brought into contact with the first Spanish invaders, they suffered much at their hands. Many references to them occur in the history of the Spanish settlers. Their appearance, social habits, and superstitious practices have much prominence given to them in the recent literature of South American travel. At present I limit my remarks mainly to the specimens of “shrunk” or reduced heads now before us. They are from several points of view remarkable, and raise several questions of great ethnological interest, but trustworthy references to them are comparatively few. Indeed, the only sources of information worth mentioning are a communication by Mr William Bollaert, F.R.G.S., to the Ethnological Society of London, 1860, and another, by Sir John Lubbock, to the Anthropological Institute of Great Britain in 1873. The former is entitled “On the Idol Human Head of the Jivaro Indians in Ecuador;” the latter, “Note on the Macas Indians.” In Mr Bollaert's paper special attention is given to a specimen obtained by M. José Felix Barriero, of the Secretariat of the Provincial Government, Quito, and sent by him to Don R. de Silva Ferro, Chilian Consul, London. This specimen was placed in the Ecuador Court of the International Exhibition, 1862. Sir John Lubbock's paper is devoted chiefly to a general description of the Macas Indians.

The design and construction of the instrument now to be described was undertaken on the suggestion of General Walker, of the East Indian Trigonometrical Survey. At the Aberdeen Meeting of the British Association in 1885, General Walker obtained the appointment of a committee to examine into the whole question of the present methods and instruments for the measurement of gravitational force, and to promote investigation, having for its object the production of gravitation measuring instruments of a more reliable and accurate character than those now in use.

Dr Albrecht of Brussels has recently traversed the well-known and generally accepted theory originally advanced by Goethe, that in the alveolar form of cleft palate the fissure lies in the plane of the suture between the intermaxillary and superior maxillary bones, and has suggested, in substitution for this theory, that in the early embryo each intermaxilla is divided into an inner mesial bone (endognathion) and an outer lateral bone (mesognathion), and that the alveolar cleft is an open state of the suture intervening between these two divisions.

My attention has been occupied of late with a chemical and microscopical study on the action of various compounds on the lower forms of plant-life. I have already presented to the Chemical Society of London a paper on the Action of a Solution of Ferrous Sulphate on certain Parasitic Diseases which attack our Crops. (This paper will be published presently.) I wish here to detail some studies on the action of salicylic acid (C7H6O3) on certain ferments (organised and unorganised). A solution of salicylic acid was prepared contaiaing 0·2 gram, of the acid in 1000 c.c. of water.

The “twist surfaces,” of which this is a case, stand in the same relation to the helicoid surface as the anchor-ring does to the cylinder. In the helicoid the generating line, at right angles to the axis, rotates about the axis as the point of intersection moves along it. In the twist surfaces the generating line is always at right angles to a fixed circle, and rotates about the tangent to the circle at the point of intersection, as the point of intersection moves round the circle. The species of twist surface is defined by the ratio of the angular motion of the generating line to that of the point of intersection. In the particular case illustrated by the model, the generating line turns through two right angles, while the point of intersection makes one whole revolution; that is, the rate of angular motion of the generating line is one-half of that of the point of intersection.

The law of variation of the electromotive force of polarisation with current-density has been very thoroughly investigated. It is found that it may be represented by an equation of the form

where x is the current-density, and a, b, c are constants. So for very feeble direct currents the reverse polarisation current is proportional to the current-density; but for strong currents it cannot be expressed by an algebraical formula as a function of the current-density in a finite series of terms. The above formula gives the maximum value of the polarisation current. So far as I know, no observations have been made regarding its variation with time from its commencement until the maximum is reached. This question is of interest chiefly from a theoretical point of view. The object of this note is to describe the result of some experiments made on this subject. Platinum electrodes, heated to redness before each experiment, were used.

While collecting materials for a Text-book of the Properties of Matter, the author had occasion to consult the very curious pamphlet by Robert Hooke, entitled Lectures de Potentia Reditutiva, or of Spring (London, 1678). In this work there is a clear statement of the principle of Synchronism, which was applied by Stokes to the explanation of the basis of Spectrum Analysis. There is also a very remarkable statement of the elementary principles of the modern Kinetic Theory of Gases, the first mention of which is usually fixed sixty years later, and ascribed to D. Bernoulli in his Hydrodynamica (Argentorati, 1738).

The first point referred to in this paper is the source of the vapour that condenses to form dew. A few observations of the temperature of the ground near the surface and of the air over it, first raised doubts in the mind of the author as to the correctness of the now generally-received opinion that dew is formed of vapour existing at the time in the air. These observations, made at night, showed the ground at a short distance below the surface to be always hotter than the air over it; and it was thought that so long as this excess is sufficient to keep the temperature of the surface of the ground above the dew-point of the air, it will, if moist, give off vapour; and it will be this rising vapour that will condense on the grass and form dew, and not the vapour that was previously present in the air.

The first question to be determined was whether vapour does, or does not, rise from the ground on dewy nights. One method tried of testing this point was by placing over the grass, in an inverted position, shallow trays made of thin metal and painted. These trays were put over the ground to be tested, after sunset, and examined at night, and also next morning. It was expected that, if vapour was rising from the ground during dewy nights, it would be trapped inside the trays. The result in all the experiments was that the inside was dewed every night, and the grass inside was wetter than that outside. On some nights there was no dew on the outside of the trays, and on all nights the inside deposit was heavier than the outside one.

The lacquer tree (Rhus vernicifera) is indigenous to Japan; it supplies a valuable timber, and its fruit yields vegetable wax, but it is chiefly cultivated on account of its juice–lacquer (Urushi)–which forms the basis of the famous Japanese varnishes. The juice is obtained by making incisions in the tree, and it is made into a varnish by simply stirring in the sun in order to drive off an excess of moisture. Different colours may be imparted to the varnish by the addition of various metals, oxides, and sulphides; and after it has been applied to an object it must be hardened by exposure to a moist atmosphere at a moderately high temperature.