14' 8 Astronomical Society. 



The high-main seam was first worked, then the Maudlin, and af- 

 terwards the Hutton, and the removal of each was attended with a 

 depression in the line of the railway. The extent of each settlement 

 was not measured, but the whole amount was 5 feet 6 inches, the 

 aggregate thickness of the seams being 14 feet II inches. This 

 small effect Mr. Buddie explains by shojving, that the railway passes 

 near one end of the excavated tract, and that metal-stone predomi- 

 nates over sandstone in the superincumbent strata. The working of 

 the five-quarter seam is now in progress, and the effects occasioned 

 by the removal of the three lower seams are well exposed. Innu- 

 merable vertical cracks pass through the coal, its roof and pavement, 

 but they are perfectly close except around the margin of the settle- 

 ment. Along this line the strata are bent down, the cracks in the 

 pavement are frequently open, forming considerable fissures, the coal 

 is splintered, and the roof-stone is shattered. In the interior of the 

 settlement the pavement is as level and smooth as if it had never been 

 disturbed, and the cracks are quite close, passing through the seam 

 without splintering it or producing any effect except that of render- 

 ing it tougher, or, in the language of the colliers, " woody." This 

 effect, Mr. Buddie conceives, may be attributed to the escape of the 

 gas, and he states that it is sometimes produced by other operations, 

 when the coal is said to be " winded," The smoothness of the pave- 

 ment, he is of opinion, is due to the direct downwai'd pressure of the 

 superincumbent mass ; and he states, that he has never noticed any 

 tendency to a sliding or sideway movement in any subsidence of 

 strata occasioned by the working of the coal, except the slight ob- 

 liquity occasioned by the offbreak at the sides of the settlement. 



[To be continued.] 



ROYAL ASTRONOMICAL SOCIETY. 



December 14, 1839. The following communications were read : — 

 On the parallax of Sirius. By Thomas Henderson, Esq. Astro- 

 nomer Royal for Scotland. 



The parallax of Sirius, the brightest star in the heavens, has 

 been several times the subject of investigation among astronomers. 

 From the variations of the zenith distances observed at Paris, the 

 second Cassini inferred a parallax in declination amounting to six 

 seconds of space ; and, from similar variations in the observations of 

 La Caille made at the Cape of Good Hope, some astronomers have 

 deduced a parallax in decHnation of four seconds. Piazzi has also 

 obtained from his observations a parallax of the same amount. On 

 the other hand. La Caille's observations of zenith distances made 

 at Paris, more numerous and certain than those made at the Cape, 

 do not exhibit any sensible parallax ; and the observations which 

 have since been made in the observatories of Europe, would appear 

 to lead to the same result, as no parallax has ever been deduced 

 from them. In the Fundamenta Astronomic, M. Bessel has in- 

 vestigated, from Bradley's Observations of Differences of Right 



