127
32. The paper must be changed every morning about 10 a. The direction and velocity are then read off by aid of divided glass scales and immediately entered in the table printed in the monthly reports. The working of the instrument has been satisfactory. It is made extra strong and worked as well in the typhoon as in a gentle breeze.
33. The pluviograph was erected in the course of January and worked without interruption since the 1st March. It is made of cast iron and stands on masonry in the ground about 75 feet S.W. of the nearest part of the main building. The rain collected by the funnel passes through a tube into a copper cup floating in mercury protected from oxidation by glycerine. As the cup is filled it sinks in the mercury and registers the amount of descent by aid of a fine lead pencil on a ruled card fastened on a cylinder revolved by clockwork. When 0.2 inch have been collected, the cup is emptied sponta- neously by a siphon arrangement, 0.1 inch of rain is represented by a length of 0.344 inch on the card, which was found correct. The hour lines are printed 0.365 inch apart, but it was not found practicable to lengthen the pendulum sufficiently for this and new hour times 0.372 inch apart have to be drawn on the cards. Care was taken by the maker to arrange, that the siphon should empty the cup as quickly as possible, and it was only during unusually heavy squalls, when the rain poured down in torrents, that it failed somewhat in its action, the amount entering the cup while it was emptying itself being lost. It was feared that the heavy rain might mechanically push down the cup, but this has scarcely been noticed in practice. For further security an ordinary rain-gauge, the rain collected in which is measured at 10 a., is kept beside the pluviograph, and it has occasionally been found advisable to correct the pluviograms by the readings of that gauge.
34. Early in the summer the place had not yet been turfed and the dust of decomposed granite raised by the wind was most destructive to the acting parts of the instruments and particularly so to the action of the rain-gauge. When the Governor last summer honoured the Observatory with his presence, His Excellency remarked this disadvantage, and the place was soon after turfed, since which time the rain-gauge has acted smoothly.
35. The pluviograms are read off by aid of a simple scale and immediately entered in the tables printed in the monthly reports.
36. The sunshine-recorder is placed in a groove in the coping stone on the parapet 34 feet above the ground. In construction and adjustment it is similar to an ordinary sun-dial, but the style throwing the shadow is replaced by a solid glass ball, which acts as a burning glass, and the hour circle consists of a blue card, on which the hours are printed, and which is changed every evening. Whenever the sun shines brightly, it burns a hole in the paper, and by comparing the burned trace with the half-hour lines it is easy to estimate, how many minutes the sun was shining every hour. The figures are immediately entered in the table printed in the monthly reports. Care is taken to keep the glass ball clean.
37. The barograph, the thermograph and the anemograph were made by Mr. MUNRO of King's Cross, London, and are as excellent specimens of workmanship as might be expected from this well- known maker. The principal part of Mr. FIGG's time has been occupied in attending to the selfrecord- ing instruments and tabulating the records,-a task in which he has exhibited much patience and perseverance as well as that conscientious care, for which he was recommended to me by Mr. WHIPPLE, Superintendent of the Kew Observatory, and to which the great accuracy of our results is to a great extent due.
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38. As stated in the "Instructions for making meteorological observations &c." meteorological instruments forwarded by observers, who regularly send their registers to the Observatory, are verified here free of cost. During the past year the following number of instruments has been verified and certificates issued:
Barometers: 13
Thermometers: 126
Anemometers: 1
39. The monthly weather reports up to July inclusive have been published. The tables are ready for the August and September reports. The typhoons in August are being investigated. The principal tables for the October and November reports are ready and some progress has been made in tabulating the records for December. I expect to be able to publish these reports in the course of next spring.
40. Some progress has also been made with the annual weather report for 1884 and with the five-day means of the principal meteorological elements. The volume of "Observations and Researches made in 1884" will be published as soon as these reports are ready.
41. The China Coast Meteorological Register was issued daily from here. Through the courtesy of the Great Northern and of the Eastern Extension Australasia and China Telegraph Companies I received daily telegrams from Wladiwostock, Nagasaki, Shanghai and Amoy, and from Manila respect- ively. Subsequently the Superintendent of the latter Company was kind enough to supply telegrams