4 02 THE POPULAR SCIENCE MONTHLY. 



discovered in the Southern Constellation (Antlia) has the surpris- 

 ingly short period of only seven and three quarters hours the 

 most rapid variation hitherto detected in any variable star. All 

 the Algol variables are white, or only slightly colored. 



It was long since suggested that the periodical diminution of 

 light in the Algol variables might possibly be due to the interpo- 

 sition of a dark, eclipsing satellite. Some few years since Prof. 

 Pickering undertook a mathematical investigation of the case of 

 Algol, and showed that an eclipsing satellite revolving in a nearly 

 circular orbit in a period indicated by the light-variations of the 

 star would satisfactorily explain the observed phenomenon within 

 the limits, of errors of observation, and he suggested that the 

 orbit might be determined by spectroscopic observation of the 

 star's light before and after the minimum. Observations of this 

 kind made by Prof. Vogel at Potsdam, in 1888 and 1889, leave 

 little doubt that the decrease of light is really due to an eclipsing 

 satellite. He found that before the minimum the bright star is 

 receding from the earth (and therefore the dark companion ap- 

 proaching), and after minimum it is approaching, thus proving 

 the eclipse theory to be correct. 



Herr J. Plassmann, of Warendorf, Germany, has lately an- 

 nounced his discovery of a secondary minimum in the light of 

 Algol and Lambda Tauri. This, if confirmed, would seem to 

 show that the eclipsing satellite is not absolutely dark, but pos- 

 sesses some inherent light of its own, this light being cut off 

 when the satellite passes in its turn behind the disk of its pri- 

 mary. The Gentleman's Magazine. 



An extensive human settlement, belonging to the stone age, has been discov- 

 ered near Schaffhausen, Switzerland, by Dr. Euesch, and is being laid bare under 

 his supervision. It is in a rocky niche, about thirteen metres high and thirty- 

 seven metres long, and is the first of that period that has been discovered in 

 Switzerland which is not connected with a cavern. The overhanging rocks 

 offered a roof as protection against the weather. Quantities of flint knives, chisels, 

 and lance-heads, bones of the reindeer, roe, stag, hare, cave-bear, and other ani- 

 mals, and human bones, needles, and the beginnings of drawings, were also found 

 here. 



A suggestion was made in Ciel et Terre, some time ago, that the date be regu- 

 larly noted, as a climatological fact, of the day, for each place on which certain 

 agricultural operations, particularly in harvesting, are begun. As the ripening of 

 the crops depends oil the absolute amount of heat they have received during 

 the season, the date of beginning the harvest will determine when the amount 

 of heat required by each plant has been accumulated. Father CI. Buve, cure of 

 Linsmeau, Belgium, suggests that the measurement of the amount of beet-sugar 

 produced from a given quantity of beets will serve the same end ; for, other things 

 being equal, it is entirely dependent on meteorological conditions. 



