AUCKLAND INSTITUTE.

Auckland Star, Volume XVIII, Issue 157, 6 July 1887, Page 5

AUCKLAND INSTITUTE.

The monthly meeting of this society was held on Monday evening. Professor Thomas presided, and there was a moderate attendance. > ! Donations.—The secretary, Mr Cheeseman, read the following list of donations to the library and museum :—Culley's Handbook of Practical Telegraphy, Mr J. A. Pond ; largo collection of Maori mats and other Maori articles.tho lateMrC. 0. Davis ; Fijian pillows, samples of Beche de Mer, Mr E. Ford ; Kiwi egg, specimens of Helix Bnsbyi, Mr H. D. MacKellar; minerals from Cornwall, auriferous quartz from the Thames, Mr W. Edgecombe; stone with Maori carving, Mr J. McElwaine; tree lizard, Mr J. Stewart; silver coin, Mr A. Black. Opening of the Museum at Night.— The Chairman said that the Council had been requested to open the Museum onpo a month at 10 o'clock on Friday morning, and in tho evening from 7.30 to 10 o'clock. He further went on to say that it would, be doubtless remembered that he personally was in favour of popularising the Museum. With this object in view it had been decided to open the Museum every Friday night instead of once a month, and he would himself be present to give a fthort popular address upon such objects of natural history as he might deem best for his audience. After tho lecture on these evenings, he would devote himself to explaining the objects in the Museum to those who wished for information. They could not at present make a complete arrangement for popularising tho Museum so as to suib tho general classes, and the changes they made would have to bo graduated.— Dr. Murray Moore, in supporting the remarks of tho Chairman, said that the arrangement spoken of would bo for three mouths, when it worild be seen if it received tho support of those classes for whom the experiment was to be tried. The Bequest or M/i C. 0. Davis. —Mr Checseman, at tho request of tho Chairman, read a most interesting paper upon tho recent gifts to the Museum by the late Mr C. 0. Davis. It was tlien carried upon the motion of the Chairman, seconded by Mr J. Stewart, " That the members of the Institute desire to oxpress the deep regTet with which they have heard of tho death of Mr C. 0. Davis, and to place on record theirappreciation of the very valuable) gift of Maori mats, carvings and other objects made to the Museum by Mr Davis shortly before his death. Mr Cheeseman's paper gave much valuable information as to tho moduli operandi employed in preparing the, flax and weaving same into the mats and cloaks before them. New Speciks of Metagly.mma. —The Secretary then read a paper by Captain T. Broun describinga new beetle belonging to a section of preclacious ground beetles. All of this class of insects are valuable to agriculturists, living as they do upon insects that destroy crops. Tick Chkomoscope.—Dr. Murray Moore read a paper prepared by Mr B. W. Bettg, tho invontor of the chiomoscope, to which wo referred some months since, giving our theory of the manner in which the phenomena were produced. The main substance of the paper read on Monday night was to the offect that certain leaf - liko forms;' upon being revolved, gave out under the action of light certain rings of colour, which the' lecturer claimed to show a new way to the determining the analogy between the forms and colours of natural objects. To illustrate his remarks Mr Betts then revolved a number of these discs, which are of cardboard and of various leaflike forms, tho point of revolution being at at their small or stalk end. A strong light was projected upon their surfaces, which, when in revolution, showed various bands of colour according to tho position of certain " stops," or slits cut through their substance in lines at a geometric tangent curve to tho point of revolution. One form showed all the colours of the spectrum, whilst on others some particularly beautiful yellows and vivid greens wero apparent. — Professor Brown said that in attempting to offer ' some explanations of the cause of the phenomena of the coloured rings upon tho revolving discs before them, lio felt some diffidence, as ho could not see many of the colours which others said they saw upon the cards. He believed that tho alternate illuminated and dark surfaces presented to the eye upon the revolving, discs produced fatigue of certain portions of the optic nerve, and illustrated what effect this would have by revolving. a disc with a circular hole in it before the lens of a magic lantern. Tho light seen when the disc was in rapid revolution was distinctly violet. The same light could bo seen when one was passing rapidly by a picket fence, through which strong sunlight was shining. Another explanation was obtainable in drawing from tho analogy presented between sound and light waves. When the source of a sound approached the observer, its tone became shriller—the sound waves coming more rapidly upon tho tympanum of the ear. The sound fell in tone as tho source passed, and distanced from the ear. This might be noticed when a whistling engine passed one upon the railway, or when a buzzing beetle passed the ear hi the bush. Applying this to Mr Betts'sbeautifulexperiments, one found that the source of light—the cardboard—being in rapid movement, was made to approach or recede to the eye, producing, as in sound, a difference in the " key," or length of tho wave. In sound, this would alter tho, note; in light, tho colour appreciated by tho eye. — Proessor Thomas, although agreeing with Professor Brown as to the cause of the effect being in the eye rather than an altertion of the ray of light, as in the case of its passing through a prism, 1 thought that the power tho optic, nerve had in retaining tho impression of various colours longer than certain others was tho answer to the rings of colour seen. If tho whole spectrum was shown to the eye for a brief space of time, only violeb was seen ; if for a longer period, red ; and so on. It was the same here ; a piece of white cardboard was shown to the eye for a brief space. The eye had only time given it to appreciate certain of its colours,, with tho result that rings of that colour were seen. —Dr. Murray Moore thought the revolving card with its "stop,", or slit, acted as a prism, allowing certain of the coloured rays of the white, or entiro ray of light, to pass through, those remaining giving the ring of colour seen.—The Chairman- announced that the first of the proposed popular papers would be read by Mr E. A. Mackecknieon July ,18th, the subject being "Pauperising the People." ■ ■ , ,i