and 15th days of the month of May is 49°0, and the number of observations 49. At first quarter, upon the same six days, the mean temperature is 52°.2, and the number of observations 38. No observations whatever for 1st, 2nd, or 3rd days after first quarter occurred upon the 10th, 11th, and 12th days of May respectively during the 43 years. Again, upon the five days of the lunation at full moon (see Table II.), out of the total number of 49 observations, 27 are found to fall below 50°, and 11 below 45°. At first quarter, out of the 38 observations, the number under 50° is 13 only those under 45° do not exceed 5. : A point of some importance in connexion with the subject should be mentioned. It did not escape Gen. Sabine's notice, when engaged on the results of the Meteorological Observations at Toronto, that high mean temperatures prevailed on the 11th, 12th, and 13th days of May on the average of the years 1841-52, at that Station, and it has since been found that they prevailed also at Greenwich during the same period; the mean temperatures of the three days for the 12 years were respectively 53°5, 53°2, and 54°1 instead of 516, 513, and 51°0, which are the means of those days on an average of 43 years. It will be found that most of the high temperatures on the three days occurred in years when the mean temperature of May itself was high*. The mean of the month for 43 years is 53°. 5. At a corresponding period of the year in autumn, the temperature of the second half of lunations which fall in October is found as a rule to be uniformly low; on an average of 43 years it does not exceed 48°9; whilst the mean of the first half (from new to full moon) is 50°4. It was so in the present year; the difference between the mean temperature of four days at first quarter and the mean temperature of four days at last quarter was 23.5 degrees. Upon extracting 14 of the lowest temperatures, or minima of 43 months of October, 13 were found to occur in the second half of the lunation between the day of full moon and the third day before new moon, and 9 of the number at and immediately following on last quarter. They occurred in the following years:— It is difficult to believe that the following dates are accidental : 1814, 1824, (and 1825), 1834, 1843; and 1817, 1828, 1838 (and 1839), 1848. The maxima in October also arrange themselves systematically. There were 4 observations of mean temperature in 43 years which exceeded 62°. They occurred in the following days and years:-viz. in 1834 on the third day after new moon; in 1819 on the second day before full moon; and in 1848 and 1859 on the day of first quarter, and second day after. In 1839 the maximum was 59'7, and it occurred on the second day after new moon. The mean of the month of October for 43 years is 49°6.-More than 75 per cent. of the maxima for the month are found to occur, in the first half of the lunation. Lastly, the amount of cloud in October for seven years has been extracted from the Greenwich Observations and formed into a Lunar Table. The mean amounts for the day preceding each of the four principal phases and * e.g. the mean of the mean temperatures of the five days at first quarter which occur on the 14th of May exceeds the mean of the five days at full moon which fall on the same day of that month by 7 of a degree only. But the mean temperature of May for the five years in which observations occurred on the above-named day at first quarter was not higher than 49°.8. In the instances at full moon it was 51°6. four following days (including in each case the day of the change) is as follows: At New Moon At Last Quarter 7.1 7.9 (the maximum). 6.9 61 (the minimum). The mean amount of cloud for the first 14 days of the lunation is 7.3; for the remaining 14 days, 6.4. The figures follow with great precision the course of the model curve and also the curve of mean temperature for 1859. It will be well to recall attention to the principle of alternation and reciprocity which so much affects the mean results of the moon's action. Many instances of the recurrence of high or low temperatures upon the same day of the lunation were adduced at the Meeting at Leeds: the following is an amended abstract of some of the more remarkable examples. In the two consecutive years commencing November 1846 and ending October 1848, maximum or minimum temperatures for the month occurred, in 1846-47, three times on the third day before new moon; twice on the day after new moon; three times on the third day after new moon; twice on the third day before full moon; twice on the second day before full moon; and twice on the third day after full moon. In 1847-48, twice on the third day before new moon; four times on the day of new moon; twice on the second day before full moon; twice on the day before full moon; twice on the day of full moon; twice on the third octant, or fourth day after full moon. Again, in the year 1846-47 there were, amongst others, the following remarkable instances of alternation between opposite phases of the moon :-in December the minimum of the month occurred on the third day before new moon; in January the maximum on the third day before full moon; in February the minimum on the third day before new moon. And again, the maximum in November 1848 fell on the day of new moon; the minimum in December on the day of full moon. In addition to this, maximum and minimum temperatures were found to occur at intervals of rather more than seven days, and that for several successive months, viz. April, May, June, August, and September, or at other lunar intervals. In 1838, exactly ten years earlier, maxima or minima occurred twice on the third day after new moon; three times on the day before full moon; three times on the day of first quarter; and three times on the day of last quarter. At the Cape of Good Hope, reciprocity of action and the recurrence of high and low temperatures was even more frequent and systematic. Thus, in 1855, eight out of the twelve maxima for the month occurred at first quarter, and nine of the twelve minima at new or full moon. In 1842, nineteen maxima and minima out of twenty-four occurred on eight days. In 1843, fifteen on seven days; in 1844, seventeen on six days; in 1845, eleven on four days. The recurrence of maxima and minima at Toronto and Madras was equally marked. On extracting the maximum and minimum mean temperatures for the month, for the respective periods of 43 years at Greenwich, and 22 years at Dublin, it was found that more maxima occurred after the moon's first quarter than before; the proportion of maxima to minima, on the second day after that phase, being more than 2:1 at both stations. So too on taking the twelve highest maxima and the twelve lowest minima at Greenwich for the same forty-three years, 48 per cent. of the whole number were found to occur on 7 days at first quarter, and minima only, with one exception, before the day of the change. Similar results were obtained from the observations taken at Toronto (from 1843 to 1848). Notwithstanding this, it is certain that the rise in the curve at first quarter and other periods of the lunation is not caused by the presence of maximum temperatures so much as the ordinary means of the several days. Though not at present able to prove the point, I may state my conviction that a close connexion will eventually be established between the occurrence of extreme temperatures (at the several periods of the lunation at which they may most probably be looked for) and the years of maximum and minimum of the solar spots. The year 1858-1859 has been already instanced as one that exhibits many noticeable examples of this increased action. The inquiry will be proceeded with; though as a non-professed Meteorologist I much need both indulgence and assistance. TABLE III. Means of the month of May, for 43 years, at Greenwich. An Account of the Construction of the Self-recording Magnetographs at present in operation at the Kew Observatory of the British Association. By BALFOUR STEWART, M.A. EARLY in 1857 the Government Grant Committee of the Royal Society voted £150 towards the expense of a set of Self-recording Magnetographs to be erected at the Kew Observatory of the British Association; the sum of £250 having been previously granted out of the Wollaston fund for the purpose of lighting the observatory with gas. The late Mr. Welsh thereupon applied himself with much zeal to the task of constructing these magnetographs, and devised a plan which was transmitted to Mr. Adie, optician, 395 Strand, who undertook to make the instruments. These were completed by Mr. Adie in a satisfactory manner, and were in operation in July 1857; by the beginning of 1858 all difficulties, whether of a mechanical or photographic nature, had been overcome, and since that date a continuous register of the magnetic elements has been obtained. With regard to the plan devised by Mr. Welsh, the best proof of its excellence is the nature of the results obtained, which may be judged of from an average specimen of the curves appended to this Report. Indeed, the |