On account of the identity of the physiological action of nitroglycerine with that of simple alkaline nitrites, it occurred to the author either that nitroglycerine was not a nitrate of glyceryl as commonly represented, but contained nitrous acid in its constitution, or that it was readily decomposed in the body with the formation of nitrous acid. This suggestion led to an extended investigation of the constitution of nitroglycerine and of the decomposing action of various substances on nitroglycerine. The conclusion arrived at as to the constitution of nitroglycerine was confirmatory of the common belief that it is a tri-nitrate of glyceryl. For it was found that although nitroglycerine yielded a large quantity of nitrous acid when decomposed by alkalies, yet nitroglycerine could not be obtained by acting on glycerine with nitrous anhydride gas, nor did the presence of urea prevent its formation when it was prepared in the usual way by allowing nitric and sulphuric acids to act on glycerine. The yield of nitroglycerine from a given weight of glycerine also closely agreed with its being a tri-nitrate, and was considerably in excess of the yield obtainable had nitrous acid entered into its constitution. An analysis of the elementary composition of nitroglycerine, which was carried out in conjunction with Mr Masson, also led to the same opinion.

Investigations have been made by Railton, Williamson, Hess and Schwab, Beckerhinn, and Sduer and Ador for the purpose of ascertaining the elementary composition and the constitution of nitroglycerine. They all agree in regarding it as a nitrate of glyceryl; but, whilst some consider that it is a tri-nitrate, others hold that it is a variable mixture of the tri-nitrate with di-nitrate and mononitrate. Their analyses are quite insufficient to establish either the one or the other conclusion, and have mainly been confined to estimations of the nitrogen. If we except a comparative estimation of the carbon with the nitrogen, there exist absolutely no determinations of the carbon or of the hydrogen. And, as the decomposition of nitroglycerine with potash has been shown to occur in a manner considerably different from that suggested by Railton and Williamson, the main reason in support of the constitution of nitroglycerine as a tri-nitrate has been removed. The authors of the present communication therefore believed that they were amply justified in making a fresh and more careful and complete analysis of the composition of nitroglycerine. Absolute determinations were made, not only of the nitrogen, but also of the carbon and hydrogen; and, in order to ascertain the uniformity in composition of nitroglycerine, the nitrogen of samples prepared by various methods was estimated. The nitroglycerine was both pure and thoroughly dried. For the determination of the nitrogen, modifications of Dumas's method and of Schloesing's method were employed. The carbon and hydrogen were estimated by a modification of Liebig's method. Every precaution was taken to insure that the results obtained should be correct. The average of the determinations gave 15 · 91 per cent, of carbon, 2 · 49 per cent, of hydrogen, and 18 · 05 per cent. (Dumas) or 18 · 14 per cent. (Schloesing) of nitrogen. Theoretically nitroglycerine, regarded as the tri-nitrate of glyceryl, contains 15 · 86 per cent, of carbon, 2 · 20 per cent, of hydrogen, and 18 · 50 per cent, of nitrogen. The quantities obtained by experiment agree so closely with the theoretical quantities that they may be regarded as affording proof that nitroglycerine is, in reality, the tri-nitrate of glyceryl. The authors also conclude, from the unvarying amount of nitrogen obtainable from variously prepared specimens of nitroglycerine, including one from Nobel's dynamite, that nitroglycerine is constant in composition and does not contain any of the lower nitrates of glyceryl, unless very imperfectly washed.

If

then will

where

hnbeing the sum of the homogeneous products of the roots of (A) of n dimensions.

I propose to describe in this essay some experiments which I have conducted upon the limits in time of separate tactile and thermal sensibilities. I shall endeavour to account for the variations seen in the limitations in conscious sensation of the different senses; and also to formulate a general proposition as to the effect on consciousness of stimuli increasing gradually in rapidity of application.

The length of the old English mile has been hitherto so uncertain, that any fresh light upon it is well worthy of study; and an important source of information—the map in the Bodleian Library— has not yet been brought to bear upon the question. The present inquiry was suggested by the sight of this map, which seems to add so much to our knowledge that a review of the whole subject has become desirable. It is proposed, therefore, in this paper to bring together all the data worth consideration, beginning with the most recent; and by deducing what the mean conclusion is from each source, to be thus able to compare together the various results, and so arrive at some definite statements within known limits of uncertainty.

Position and Importance of the Cell Theory in Morphology.—Vast though is the literature of vegetable and animal morphology, it becomes more readily grasped than that perhaps of any other science, when we classify it in relation to the few great works which initiated and for ever mark the successive waves of advance. Thus of the early pre-morphological or encyclopædic stage, when materials were being little more than heaped together, the works of Pliny or Gesner may be taken as types, to which the other encyclopædias of Natural History by Jonston, &c, furnish at first mere supplements. The Systema Naturæ of Linnæus closes the old and marks a new era, and initiates that systematic enumeration of the flora and fauna of the globe which has since made such vast progress. All subsequent systematic literature, no matter how important, no matter how much exceeding in quantity of new forms, involves no essential, no qualitative advance: thus the greater part of the proceedings of such Societies as the Zoological or the Linnean, such new and important faunistic literature as that contained in the magnificent volumes of the “Challenger” Expedition, or even the greatest systematic works, find their highest place not as superseding, but as supplementing the fundamental classic of Linnæus.

The object of this short paper is to give the results of some further experiments made with a view to determine the variation in the Peltier Effect due to change of temperature. These experiments are the continuation of a set of similar experiments described in a paper read to the Society in summer 1882.

That of the lathe-band is one of those simple-looking problems in elementary mechanics which present serious difficulties to the investigator. The problem is this—“So to arrange the several diameters on the fly-wheel and pulley cone of the turning-lathe, as that the same band may suit for all.” The solution consists of two steps converse to each other, the one being “to compute the length of the band from given diameters,” the other “to compute new diameters which may suit the length so found.”

The following notes have been compiled from my own observation, when in Central Africa in 1880, from inquiries I made on the spot, and from the information I have obtained from a native who has been my faithful servant during the past few years.

This communication falls conveniently into two sections—I. dealing with the specimens obtained by H.M.SS. “Lightning” and “Porcupine,” during what may be called the pre-Challenger period of deep-sea exploration; II. concerning those dredged by the “Knight Errant” and “Triton” during the surveys of the Wyville Thomson ridge, which were conducted in the years 1880–82.

The only observations, so far as I am aware, that have been made on the pitchers of Nepenthes seedlings, are those by Sir J. D. Hooker, who, in 1859, described their external configuration in his paper “On the Origin and Development of the Pitchers of Nepenthes, &c,” in vol. xxii. of the Linnean Society's Transactions, and afterwards added a few details of anatomical structure, in his admirable address on Insectivorous Plants, delivered at the Belfast meeting of the British Association in 1874.

In the progression of fractions here used, each new term is got by corresponding multiples of the three preceding terms, thus:

this mode of formation being applied separately to the numerators and denominators of the fractions.

1. During the present year there has appeared at intervals, in the Comptes Rendus of the French Academy, quite a series of communications by M. E. de Jonquieres, on the subject of those periodic continued fractions which are the equivalents of the square roots of integers. These communications have attracted attention, both on account of the number of results given in them, and because, as a writer in the Bulletin des Sciences Mathématiques says, of their interesting and profound character. To any one really intimate with the bibliography of the subject, this cannot but be a little surprising. It is true that the number of so-called theorems is great; but the very special character of a number of them, the fact that they are just such theorems as may be obtained by experiment and induction, and the want of demonstrations of them as evidence that the author was in possession of a mathematical theory of the subject, are points that have been too much overlooked. Further, and what is more important, many of the theorems are not new, and there is a sense in which the epithet “new” cannot fairly be applied to any of the earlier ones, because of the existence of a widely general theorem in which they are directly included, or from which they may with readiness be deduced.

The new forms have been found in the palms of the raccoon, the Procyon lotor, so named from its habit of dipping its morsels in water before eating them. These forms are three in number, and, in order to prevent any morphological or physiological appellation being applied to them, they have been named, for purposes of description and differentiation, after three ladies respectively, the Browne, the Hoggan, and the Blackwell bodies. The Browne bodies occupy the apices of the dermic papillae, exactly where the Meissner bodies are found in man, monkeys, and marsupials; otherwise they have no resemblance to these bodies. Properly speaking, they are not bodies, but only forked terminations of the nerves, formed generally of two or three prongs, and these are twisted and intertwined in an intricate manner. Nor do they possess any capsular envelopes, the presence of which differentiates them from the Hoggan bodies, that being the only distinct difference between the two.