420 



NATURE 



{March d, 1879 



tions; and in addition, strong feelings, we may almost 

 add of animosity, towards the writers whose opinions he 

 sets himself to combat. The result is a readable book, 

 containing much valuable information to those who intend 

 visiting Rome, though occasionally marred by the intro- 

 duction of hasty writing and hasty feeling. In comparing 

 (p. 151) the mortality from typhoid in London in 1870 with 

 that of Rome in 1876, the deaths in London are stated to 

 have been 2,008, or 10 per cent, higher than the deaths 

 in Rome ; whereas the deaths from typhoid in London in 

 1870 were only 976, giving a mortality from this disease 

 of little more than half that of Rome, Teehnical know- 

 ledge also on occasions fails the author ; thus it is 

 strongly asserted (p. 120) that the diurnal fall of tempera- 

 ture takes place almost exclusively between 3 p.m. and 

 sunset, and between 9 or iop.m. and sunrise, but the two 

 hours after sunset are those when the temperature is 

 most nearly stationary. The mortality statistics, now 

 published weekly by Coechi, will soon supply information 

 for a satisfactory handling of various questions which 

 have been raised touching the health of Rome. 



The Missouri (U.S.) Weather Service Report for 

 January last is just received (February 24), from which 

 we learn that at St. Louis the temperature did not rise to 

 freezing from December 11 to January 15; the mean 

 temperature of the first ten days of January was only 

 9°*o, and that of the whole month 26°'9, or 4°7 below the 

 average ; and at Oregon, in the north-west of the State, 

 the sleighing season ended on January 25, after a con- 

 tinuance of fifty days. The lowest observed temperature 

 was - 24" "o at Phelps City on the 3rd, and at Columbia 

 on the 4th, and temperatures nearly as low were noted 

 on these days at many other places. The rain- and snow- 

 fall was moderate in amount, being about two inches in the 

 extreme south-east and south-west and along the low 

 country round the mouth of the Missouri, whilst in the 

 north the fall was considerably under an inch of rain and 

 melted snow. The cold of January, 1857, was much 

 more intense than during last month, the mean tempera- 

 ture of that month being only i9'-3, or i2°-3 below the 

 average. It is delightful to note the frank, effective man- 

 ner in which Director Nipher is bringing about uniformity 

 in his observers' reports; thus, after pointing out that 

 ^' rainy " or " snowy " days are only those on which the 

 rain or melted snow amounts to at least o"oi inch, he 

 adds that "this international rule is almost universally 

 disregarded by our observers." 



The meteorological observations made at the Hydro- 

 graphic Office at Pola during 1878 have been issued, with 

 a full abstract for the year, showing the hourly means of 

 pressure, temperature, and wind-velocity. The most 

 prevalent winds by far are from the quarter of the com- 

 pass from east-north-east to south-east, these comprising 

 nearly half the winds of the whole year, to which there is 

 to be added a small secondary maximum of west-north- 

 west winds. The wind falls to its daily minimum velocity 

 at 5 to 6 A.M., and rises to the maximum so early as noon, 

 hours all but coincident with the daily maximum and 

 minimum temperature. From the three years' observa- 

 tions now available from Pola, it is seen that in common 

 with sea-side stations of the middle and higher latitudes, 

 the A.M. maximum of pressure occurs later in winter than 

 in summer, in contradiction to inland places where it 

 occurs much earlier. Pola being in latitude 44° 52' north, 

 and thus within the belt to which Rikatscheff drew atten- 

 tion some time ago, as characterised by the occurrence, 

 or tendency toward the occurrence, of a third maximum 

 of pressure a little after midnight during the cold months 

 of the year, it is interesting to note that four out of the 

 nine individual Decembers, Januarys, and Februarys, 

 show the occurrence of this third maximum, which also 

 appears in the general means of December and January 

 for the three years. % The amount of this third maximum 



is very small, and the evidence yet adduced is not suffi- 

 cient to determine whether it is a real increase of atmo- 

 spheric pressure, or merely an apparent increase due to 

 undetected instrumental errors. 



OUR ASTRONOMICAL COLUMN 



Brorsen's Comet. — Notwithstanding the track of this 

 comet at the present appearance is a very favourable one 

 for observation in these latitudes during April and May, 

 the theoretical intensity of light at maximum is much less 

 than that attaching to the first appearance in 1846 ; 

 indeed, in the middle of April, when it is greatest, it is 

 only half that of the middle of March 1846. The comet 

 in that year was never a conspicuous object in ordinary 

 telescopes ; it approached pretty near to the eacth, and 

 on March 25 its apparent diameter was about 9', corre- 

 sponding to a true diameter of 126,000 miles. 



The following positions for part of the present month 

 are reduced to 7h. Greenwich time from Dr. Schulze' s 

 ephemeris, which has been calculated for Berlin noon •— 



N.V.D 



..8259-8 

 ..81 o*o 

 .•78 55-8 

 •• 76 47*3 



The comet will be nearest to the earth (distance = 0-683) 

 on the night of May 3, its position at the time being 

 between 49 and 55 Camelopardi. Between April 14 and 

 June II it will not descend below the horizon of^ Green- 

 wich, attaining its greatest north declination (65° 30') on 

 May II, in the head of Ursa Major. The comet was 

 found by Dr. Tempel, as abready stated, on January 14, 

 more than a month before the ephemeris by Dr. Schulze 

 commences, and as we remarked in a former note, was thus 

 observed with a much less intensity of light than at any 

 previous opposition. The error of the ephemeris has not 

 yet been published, but it appears not to be large. We 

 shall continue the ephemeris in due course when better 

 advised on this point. 



In his report upon the work of the Observatory of 

 Leipsic in 1877, Prof. Bruhns mentions that Herr Harzer 

 a student in that university had, at his request, re- 

 determined the effect of the attraction of Jupiter upon 

 the elements of the comet at the near approach of the 

 two bodies in May, 1842, and with satisfactory results. 

 In 1857 the late Prof. D'Arrest made a first approxima- 

 tion, by the method of the Micanique Celeste, to the orbit 

 which the comet described prior to the great perturbation 

 or on entering the sphere of activity of Jupiter about 

 April 19-5 Berhn time in 1842; the elements at that 

 epoch were found to be as follows (we annex the elements 

 in 1846 at the time of the comet's first discovery for the 

 sake of comparison) : 



Long, of perihelion 



,, ascending node 



Inclination 



Excentricity 



Perihelion distance 

 Log. semi-axis major ... 

 Period 



1842, April i9"5. 



133° 26'-; 

 107" 44 -o 



40° 5i'-o 



0-59275 



I -50130 



0-56661 



7-078 years. 



1846, Feb. 25-4- 



116° 28'-2 



102" 4i'-o 



30° S5'*9 

 0-79338 

 0-65013 

 0-49783 

 5-581 yeai-s. 



It will be seen that the perihelion distance before the 

 encounter with Jupiter was much greater than it now is, 

 a sufficient reason, as was pointed out by D Arrest, tor 

 this comet to have been missed, if it had moved in the 

 orbit Avhich was so much changed in 1842. 



Minor Planets.— M. Palisa notifies his discovery of 

 No. 192 at Pola on February 17. At 13^- 47m. m.t. its 

 R.A. was iih. lom. 205., and N.P.D., 84° 6 , eleventh 

 magnitude. , v- u • 



Hilda, the most distant of the minor planets, which 15 



