198 ANNUAL OF SCIENTIFIC DISCOVERY. 



BAROMETRIC ANOMALIES ABOUT THE ANDES. 



Lieutenant Maury, in a communication to SilUmari's Journal, gives the fol- 

 lowing account of some very curious barometric anomalies observed by 

 Lieutenant Hernden in the vicinity of the Andes of South America. This 

 officer, who explored the Valley of the Amazon, and determined the heights 

 of various places above the level of the sea, both by barometric pressure and 

 by the boiling-point of water, states that at the eastern base of the Andes he 

 found the pressure of the atmosphere, as measured by the temperature of boil- 

 ing water, to be nearly as great as it is usual at the sea level ; and after 

 having descended the river for nearly a thousand miles below this place of 

 great pressure, he found that, judging by the boiling-point of water, he had 

 ascended nearly 1,500 feet. The explanation offered by Lieutenant Maury of 

 this phenomenon is as follows : The Andes extend from 3 to 5 miles up into 

 the atmosphere. The trade winds blow almost perpendicularly against them, 

 of course these winds are obstructed by an obstacle which extends as far up, 

 or nearly as far up, as they themselves do ; and being thus obstructed in their 

 course, would produce a banking up of air against their slopes, as there is of 

 water against a rock or other impediment over which the current of a rapid 

 river has to force its way. In such case there would be a ridge or pile of 

 water above the obstruction, and a depression or hollow in the water both 

 above and below this ridge. The same effect is doubtless produced in the at- 

 mosphere. Admitting this to be true, we derive a practical rule that the 

 height of a chain of mountains, determined by barometric pressure, depends 

 upon the way the wind blows. 



NEW PLANETARIUM. 



Mr. J. W. Hatch of Utica has nearly ready a Planetarium, the largest ever 

 constructed in the United States. In this model the planets are made to re- 

 volve in vertical orbits. These are projected on a screen or medium, behind 

 which all the machinery is concealed, so that there appears no visible sustain- 

 ing power between the planets and the sun. The whole is arranged with 

 folding-curtains, by which the celestial scenery can be brought on with 

 theatrical effect. The eclipses of the satellites take place as they come into 

 that part of their orbits relative to the sun to produce those results. The 

 great comet of 1680 is represented traversing an elliptic orbit through a circuit 

 of 50 feet. 



NEW HYGROMETRIC REGULATOR. 



A hygrometric regulator exhibited at the Fair of the American Institute by 

 Dr. Joel H. Koss, is designed to equalize the condition of the air with regard 

 to moisture, irrespective of temperature. Dr. Ross's plan is especially designed 

 for buildings warmed by steam-pipes. He attaches a cock to blow a stream 

 of vapor into the room, and makes the cock self-adjusting by the aid of a 

 weight and a long linen string. The weight continually strives to open the 

 cock, while the string restrains it ; but as the linen fibers are contracted by 





