304 ANNUAL OF SCIENTIFIC DISCOVERY. 



clitions of the earth. The elliptical form of the earth's orbit brings 

 us about 3,000,000 miles, or nearly 3 percent., nearer to the sun, 

 at about the season of " January thaw." This is the case at pres- 

 ent ; but a regular change is going on in the proportions of the 

 ellipse marked by the earth's annual revolution, which would in 

 process of time so much flatten and elongate it as to increase the 

 difference between the greatest and least radius to as much as 14,- 

 000,000 miles. At the same time, the month of January is grad- 

 ually rotating from the nearest to the remotest and coldest posi- 

 tion. At the suggestion of Sir Charles Lyell, a calculation was 

 undertaken some time ago by Mr. Stone, chief assistant at the 

 Royal Observatory, England, to determine the period of the ex- 

 treme difference. The calculation was too vast to be completed 

 at the time, but it was carried far enough to show that 210,000 

 years before A. D. 1800, the difference amounted to as much as 

 10,500,000 miles. Again, there is a small but constant change 

 going on in the direction of the axis of the earth, which runs 

 through all its variations in about 26,000 years ; so that the posi- 

 tion of a given latitude, relatively to the sun, would vary from the 

 aspect or exposure of minimum warmth to that of maximum 

 warmth in about 13,000 years. The importance of these points 

 of contact between astronomical and geological researches can 

 not fail to be developed by the devotees of science. Scientific 

 American. 



THE INFLUENCE OF THE MOON UPON THE WEATHER. 



Prof. Marcet, of Geneva, who has worked upon the meteorologi- 

 cal tables from 1800 to 1860 in the " Bibliotheque de Geneve," has 

 given the results in tables in the same journal. During the last 

 60 years (21,915 days, 742 lunar months) there have occurred 

 2,630 changes of weather that is, from rainy to fine weather, or 

 fine weather to rainy. Of these 2,630 changes, 93 happened at 

 new moon, and 90 at full moon ; 109 occurred on the day follow- 

 ing the full moon, and 107 on that following the new moon. It is 

 hence calculated that the probability of a change of weather oc- 

 curring on the day of the full moon is 0.121 ; at new moon, 0.125 ; 

 the day after full moon, 0.143; the day after new moon, 0.148. 

 The influence of the moon upon the number of days of rain, and 

 the quantity of water which tails, the professor regards as nega- 

 tive. With reference to the barometer, he states that, of the 2,630 

 changes of weather, the barometer prophesied 1,960 times cor- 

 rectly. This approaches nearly to the proportion of three times 

 out of four. 



ON THE PERIODICAL VARIATIONS OF TEMPERATURE. 



M. Ch. Sainte-Claire Deville has established, in a former me- 

 moir, that there exists a certain depending connection in the move- 

 ment of the mean temperature of four days, placed on the ecliptic 

 at an angle of 90 one from the other, for the four months, op- 

 posed two by two, of February, May, August, and November, 

 which contain the critical days, known by the ancients under the 



