PROGRAMME OF THE HOLLAND SOCIETY OF SCIENCES OF HARLEM, 1869.

The Holland Society of Sciences, held at Harlem, 15 May, 1869, its hundred and seventeenth annual session. The President-Director, Baron F. W. van Styrum, opened the sitting with an address in which he recalled the losses sustained by the society since its last general meeting; those, namely, of the director Baron G. F. Thoe Schwartzenberg at Hohenlansberg, of the native members G. Simons, H. C. Millies and J. van Lennep, and of the foreign members K. F. P. von Martius, at Munich, J. Plücker, at Bonn, H. von Meyer, at Frankfort-on-the-Maine, and C. S. M. Pouillet, at Paris. Finally, the nomination of M. G. Willink de Bennebroek, as a director of the society, was announced. Since the last annual meeting the society has published: Archives Néerlandaises des Sciences exactes et naturelles, parts 3, 4 and 5 of vol. iii, 1 and 2 of vol. iv.

In reference to a proposition submitted by MM. J. P. van Wickevoort Crommelin, D. de Haan, J. van der Hoeven, J. P. Delprat, R. van Rees, A. Hvan der Boon Mesch, D. Lubach, and V. S. M. van der Willigen, and for the consideration of which a committee was appointed at the last general meeting, composed of the directors G. F. van Tets and J. P. van Wickevoort Crommelin, and of the members V. S. M. van der Willigen, G. de Vries, C. A. J. A. Oudemans, P. Harting and E. H. von Baumhauer, the society adopted the following as its decision:

1st. Besides the medals decreed for questions proposed for competition, the society ordains two new medals, each of the intrinsic value of 500 florins, one of them to bear the name and effigy of "HUYGHENS," the other those of "BOERHAAVE." 2d. These medals shall be alternately awarded, every two years, to the savant, whether Netherlander or foreigner, who by his researches shall, in the judgment of the society, have most contributed, during the last twenty years, to the progress of some definite branch of the physico-mathematical sciences or of the natural sciences. 3d. The Huyghens medal shall be assigned in 1870 to physics, in 1874 to chemistry, in 1878 to astronomy, in 1882 to meteorology, in 1886 to mathematics, (pure and applied.) The Boerhaave medal shall be assigned in 1872 to mineralogy and geology, in 1876 to botany, in 1880 to zoology, in 1884 to physiology, in 1888 to anthropology; and thereafter in the same recurrent succession. 4th. The preliminary judgment on the respective titles shall be referred to a committee named by the directors; of which committee the secretary of the society shall always be a member. 5th. The medal shall always be awarded by the general assembly, on the detailed and analytic report of the committee of judgment.

The following question having been offered for competition in 1865 and continued in 1867: "The society requests an exact description, with figures, of the skeleton and muscles of the Sciurus vulgaris, compared with what is known on this subject of the Lemurides and the Chiromys, in order that the place to be assigned to this last species in the natural classification may be determined with more certainty than has been heretofore possible;" a reply has been received through a memoir in the Dutch language, bearing the motto: Beter is het te pogen zonder te slagen dan stil te zitten uit vrees voor nutteloose moeite. (Better is it to endeavor without succeeding than to sit still from fear of profitless labor).

On the advice of the referees, the assembly awarded the gold medal to the author of the above memoir; which, upon the opening of the sealed note, was found to be the joint production of Dr. C. K. Hoffmann, adjunct physician at Meerenberg, and of M. H. Weijenbergh, jr., surgeon and accoucheur at Utrecht. Of our own countrymen, the members elected at the session in question were MM. E. H. Beima, keeper of the museum of natural history at Leyden; R. P. A. Dozy, professor in the faculty of philosophy and letters at Leyden; J. F. W. Conrad, engineer-in-chief of the Waterstaat, at Middlebourg. Of foreigners, the following were at the same time elected members of the society: MM. L. Á. J. Quetelet, from Brussels; W. Sartorius von Waltershausen, from Gottingen; A. W. Hofmann, from Berlin; J. D. Dana, from New Haven.

The president notified the assembly that the library, put in order and provided with a catalogue by the care of the secretary, is now at the disposal of the directors and members of the society.

The Society offers for competition the following questions, the answers to which must be addressed to it before the 1st of January, 1871:

I. The knowledge of the peat-bogs of the Netherlands, as well the higher as the lower, is yet far from being complete. There remain many researches to be made before we can determine with precision what are the plants of which they are composed; in particular, what are the ligneous substances found therein, and what the succession of the different vegetable species in the series of the beds of these peats, from the most ancient to those which still continue to be formed. The society desires to see this subject elucidated, and suggests consequently a thorough microscopic examination of the plants composing the Netherland peats. II. The society requests an exact description of all the chemical or physical operations in which have been obtained, whether accidentally or by virtue of direct experiments, those chemical combinations which, by their chemical and physical characters, accord with the inorganic compounds existing in nature, under the form of minerals. The production of new artificial minerals is not asked for, but simply the critical appreciation of results already realized, with the exact indication of the works and memoirs in which the known artificial minerals have been described; in the classification of these products, conformity should be observed with some one of the mineralogical systems most extensively accepted.

III. The society considers it desirable that a description of the fossil flora of some of the coal deposits of Borneo should be given, and a comparison of that flora with those of other coal formations.

IV. The society desires a monograph of the substances called albuminous; this monograph should comprise an historical review of the numerous researches to which these substances have given rise and a critical appreciation of the opinions which at present maintain a footing in science with regard to this subject. V. The society asks that the co-efficients of dilatation of different kinds of glass, especially of those which serve for the construction of thermometers, should be exactly determined, according to the method of M. Fizeau, between -30 and 500 degrees of the centigrade thermometer.

VI. Recent researches seem to confirm the opinion that the bodies called hydrates of carbon are polyatomic alcohols; the society invites new researches calculated to elucidate this important point.

VII. The determination of temperatures higher than 350 degrees of the centigrade thermometer still leaves, in all cases, much to be desired; the society will confer its gold medal for the construction of some very simple apparatus which shall give the temperatures up to at least 500 degrees of the centigrade scale.

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VIII. The society solicits exact determinations regarding the variation of the indices of the refraction of water, for at least 12 points of the spectrum, on an extent of 50 degrees of the centigrade thermometer.

IX. It is known that the aurora borealis gives rise to telluric electrical currents which sometimes introduce considerable perturbations in the service of telegraphic lines. The society regards it as an object of interest that on telegraphic lines of great length determinations of the force of those currents should be made, to the effect, among others, of ascertaining to what point they extend towards the equator.

Questions to which an answer must be returned before 1st of January, 1873.

I. The society desires a complete critical review of the different phanerogamic floras of Europe, as well of those which have been published separately as of those which are to be found in the transactions of learned societies and in scientific journals. This review should be so arranged that the details concerning each country or province shall be mentioned in succession one after the other, according to the date of their publication. The work must be accompanied with critical observations relative to the greater or less value properly to be attributed to each flora, and to the opportunity afforded of deciding on the indications observed, or of proceeding to new researches in countries little known.

II. The society calls for a complete critical review of the different faunas of Europe, as well of those which have been published separately as of those which are extant in the collections of learned societies and in scientific journals. This review should be drawn up in the same form as regards arrangement and with the same conditions as those prescribed in the preceding question with reference to the different floras of Europe.

The following questions were last year submitted to competition by the society with a view to their being answered before the 1st of January, 1870:

I. Since the progressive decline and final suppression of the governmental culture of spices in the Molucca islands, it has become highly desirable that new lines of culture should be established in that fertile archipelago. The society consequently asks: (1.) A description of the present social condition of those islands, especially as regards the population and its aptitude for agricultural industry. (2.) Indications of the varieties of the soil, considered in relation to the culture proposed for eventual adoption. (3.) Statistical data on the results of the free cultivation of spices, as it is now practiced. (4.) A statement of the result of the experiment of cultivating cacao, undertaken by order of Governorgeneral Pahud and with the effective support of the government. (5.) A detailed specification of the vegetables, the culture of which would deserve to be tried among those whose products are suited for exportation.

II. It cannot be denied that spectral analysis, as at present conducted, tends to fall into excess and that its value is frequently exaggerated. Consequently, and in order to arrive at views at once more sound and of a more scientific character, it is required to make an equitable separation of the true from the false, to trace the limits within which the method may be legitimately employed and beyond which it ceases to be applicable, to submit to a sober critical appreciation the facts which it has brought to light, the discoveries which it promises, and those which we have a right to expect from it.

III. The galvanic current heats the metallic conductor which it traverses; by this, the resistance of the latter is augmented, and in this way the current reacts

on itself. On the other hand, it may be supposed that the intensity of the current further modifies the value of the resistance by virtue of an action which does not directly depend on the heating. It is desirable that, in one and teh other point of view, the influence exerted by the intensity of the current or the degree of the resistance, should be studied. Among the metals susceptible of being employed in this inquiry, mercury would seem to be one of those which offer the most advantages.

IV. The society solicits a criticism, as well as a repetition and extension of the experiments on the electrolysis of the melted haloid salts, (Faraday, Experimental Researches, vol. i, art. 538 et seq. and 978 et seq.,) together with an exposition of the considerations which are deducible therefrom on the nature of electrolysis.

The law of Faraday on electrolysis is extremely simple; but the question is far from being exhausted, and the ensemble of the phenomenon is as yet covered with a thick veil. Hence it is especially desirable to determine to what point the before-cited experiments are in opposition to that higher view, supported by a great number of facts, agreeably to which no true electrolysis can take place unless the action of the current is exerted on double salts or on combinations which are equivalent and analogous to them.

V. According to M. G. Ville, (see Revue des Cours scientifiques, 1868, No. 7, p. 103,) nitrogen in a free or elementary state is assimilated by certain plants, particularly by leguminous plants. The society wishes that this opinion should be submitted to a critical examination, and that its exactness or its falsity be established theoretically or experimentally, and preferably by both methods.

VI. In regard to the experiments of M. Graham, the society calls for new researches on the solutive power of melted metals for hydrogen, particularly with a view to deciding whether there exist definite combinations of metals with hydrogen.

VII. The society asks for an exact description, accompanied with figures, of the changes undergone by the organization of the Batrachians during their metamorphosis.

VIII. The assertion that metals become transparent at a temperature sufficiently elevated, requires to be confirmed or invalidated by experiments made on several different metals.

IX. The society wishes to have it experimentally determined whether the luminous power of the Lampyris noctiluca et splendidula (Linn.) should be attributed to the secretion of a particular matter, and if it be so, that the nature and composition of that matter be investigated.

X. There still exists much obscurity respecting the cause of the phosphorescence of the substances which bear the name of artificial phosphorus. The society invites a thorough investigation, to the end of deciding the question whether that phosphorescence should be attributed solely to a slow oxidation.

XI. Whilst, in meteorological observations, the pressure and temperature of the air, the direction and force of the wind are observed in a continuous manner, by means of registering instruments, we are always reduced, as far as the humidity of the air is concerned, to isolated observations made at certain hours of the day. The society desires the construction, whether upon new principles or such as have been already indicated, (see Poggendorff's Annalen, vol. 93, p. 343,) of a registering instrument for the determination of the humidity of the air, and solicits a communication of the results of observations made with such an instrument and continued during at least half a year.

XII. A memoir on the life of Koopman (Mercator) and of Ortels, (Ortelius,) and on the services which these two savants have rendered to geography, ethnology, and cartography, is regarded as a desideratum.

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XIII. The society would wish that the biography of the Baron van Imhoff, and the history of his administration as governor-general of the Dutch Indies, should be written from documents not heretofore made use of.

XIV. The society invites an analysis of the life and a narrative of the voyages of Dutchmen who, in the 17th and 18th centuries, distinguished themselves as navigators or as authors of geographical discoveries.

XV. What has been done up to the present time, for the study of the languages of the populations subject to the domination of the Netherlands in countries beyond the sea, and what are the vacuities which it would be chiefly important to supply in this respect?

The Society recommend to competitors to omit in their replies all that has not an immediate relation to the question proposed. It hopes to find in everything submitted to it perspicuity united with brevity, and demonstrated propositions clearly distinguished from vague considerations and facts imperfectly established. It is further to be remembered that no memoir written by the hand of the author will be admitted to competition, and that, even were a medal awarded, its delivery would not take place if, in the meantime, the hand of the author should be recognized in the work accepted.

The notes attached to memoirs which fail to receive the prize shall be destroyed without being opened, unless it shall have been discovered that the memoir presented is but a copy extracted from printed works; in that case the name communicated will be divulged. Every member of the society shall have a right to take part in the competition, on condition that his memoir, as well as note, shall be signed with the letter L. The memoirs, written legibly, in Dutch, French, Latin, English, Italian, or German, (but not in German characters,) must be accompanied by a sealed note containing the name of the author, and be sent free to the secretary of the society, Professor E. H. von Baumhauer, at Harlem. The prize offered for a satisfactory reply to each of the questions proposed, consists, at the choice of the author, either of a gold medal, bearing the usual stamp of the society, the name of the author and the date, or a sum of 150 florins; a supplementary premium of 150 florins may be added if the memoir be deemed worthy of it. The competitor who shall receive the prize will not bo allowed to print his memoir, either separately or in another work, without the express authorization of the society.