500 T)v. G. Neumayer on the Lunar [May IG, 



range of the epoclis of syzygy (R^) and that for the epochs of quadra- 

 ture (R^i). 



Months. 



Lunar-divirnal range in pressure of air. 



Difference, 



Full 

 moon. 



New 

 moon. 



First 

 quarter. 



Last 

 quarter. 



Mean for the 

 epochs of 



c< 1 Quadra- 

 Sy ^ture. 







September . . . 



October 



NoTember ... 

 December ... 



January 



February . . . 

 March 



in. 



0-1507 

 •1312 

 •1125 

 -1656 

 -1532 

 -2103 

 •1597 

 •1318 

 •1907 

 -1729 

 •1073 

 •1262 



in. 



o"i632 

 •1730 

 -146I 

 •1311 

 •1585 

 -1667 

 •2038 

 •1582 

 •2191 

 •1287 

 -0662 

 •1509 



in. 



0-1728 

 •1669 



*i 557 

 -1451 

 •1095 

 •1497 

 -1797 

 •1648 

 •1226 

 •1518 

 •1246 

 •1155 



in. 



0-1224 



•1399 

 •1282 



-1145 

 •1872 

 •2071 



•1557 

 ■2208 

 •1800 

 •2059 

 -1154 

 -1448 



•16016 



in. 



0-15695 

 •15210 

 •12940 

 •14835 

 •15585 

 -18850 



•18175 

 -14500 

 •20490 

 -15080 

 •08675 

 •13855 



in. 



0-14760 



•15340 

 •I4I95 

 •12980 



•14835 

 •17840 

 •16770 

 •19280 

 •I5I3O 

 •17885 

 •12000 

 •13015 



in. 



+0-00935 



— "00130 



— -01255 

 + -01855 

 + -00750 

 + -oioio 



+ -01405 



— -04780 

 + -05360 



— -02805 



— -03325 



+ -00840 



Means 



-15101 



•15547 



-14656 



•153242 



•153360 



— -000118 



The last column of this Table shows the difference R^ — R*!, so that plus 

 denotes an excess of the lunar-diurnal range at the periods of syzygy, and 

 minus an excess at the periods of quadrature. 



According to the above there is a decided minimum in the lunar-diurnal 

 rangje at the time of the first quarter, while the last quarter seems to be 

 the maximum, the time of the syzygy showdng intermediate values. The 

 general mean would indicate an excess, though very small, in favour of the 

 epochs of the quadrature. On examining, however, the difference for the 

 single months, we notice that the algebraic sign denotes for seven months 

 an excess of the epochs of syzygy, and for five only the contrary ; 

 further, that the greatest irregularity in respect to the signs and values 

 prevails durings the months from November to February, when hot winds 

 are most frequent, and the sudden changes in temperature, connected with 

 these phenomena, cause the oscillations of the barometer to be much dis- 

 turbed. The magnitude of the values during this period ought to induce 

 us to receive them Vvith caution, and to consider the eight remiaining 

 months separately. The general mean difference for the eight months, 

 from March to October, both inclusive, represents an excess in favour of 

 the epochs of syzygy of 0-0067G2 inch, a value which most probablj^ makes 

 a near approach to truth. 



If we derive mean values of the lunar-diurnal range for the several years 

 of observation at the respective phases of the moon, we have — 



i 



