Astronomical Expedition to California.

Harvard has made great preparations to observe the total eclipse of the sun on Jan. 1. 1889, and for that purpose has already sent a great deal of apparatus to California. The eclipse will be visible no further east than New York state, and there only at sunset, but the line of the centre of the eclipse will pass just to the north of San Francisco,

The temporary observatory is to be built at a town called the Willows, about two hundred miles north of Sacramento, and from two to three hundred feet above the level of the sea.

The largest telescope which has heretofore been used for this purpose had an aperture of only six or seven inches, but the telescope which has been sent out has an aperture of thirteen inches. Also there have been sent two telescopes of eight-inch aperture, besides numerous other instruments, such as photographic cameras and devices for observing the spectrum of the edge of the sun and of the different parts of the corona separately.

The corona of the sun is to be the special object of study by those who go from Harvard, for which purpose the apparatus has been so arranged as to permit the photographing of eight different regions of the spectrum of the corona at the spectrum of the corona at the same time, which will be wholly in the green and yellow parts of the spectrum. Other apparatus will take photographs of the blue region and the ultra-violet, or that which it is beyond the power of the eye to perceive. The plates will not be developed at Willows but they will be brought out leisurely either at Cambridge or at Southern California where the party is to go, after the eclipse is over, to work for the benefit of the University of California.

One of the instruments which will be used during the eclipse is for the purpose of determining whether it is probable that some of the demands which are classified here as simple, are not really compound, and are separated in the intense heat of the sun. It has been suggested that iron may be a compound of calcium and oxygen, and that these elements may be separated in the sun. So this apparatus will take the light of the very edge of the sun just as the eclipse becomes total, then of the bottom part of the corona, and then of the outer part. If it is found that some of the lines of the spectrum which appear in the photographs of the edge of the sun and the bottom of the corona, are not found in the outer part of the corona, or if some are found in the outer part of the corona which are not found in the bottom, then it will be probable that such separation does exist, and that chemical elements which are now accepted as simple are really composite.

A search will also be made for the intra-Mecurial planet, about whose existence astronomers are very much in doubt.

The party will be under the charge of Prof. William H. Pickering and will consist of S I. Bailey, E. S. King, and Robert Black from the Cambridge observatory, and Mr. A. L. Botch, who is not connected with the university, and who will have charge of the meteorological work of the expedition.

Mr. Bailey will go from California to Peru where a branch of the Cambridge observatory is to be established for the purpose of studying the spectra of the stars in the southern heavens, which are not visible in Cambridge.

After Mr. Bailey has been there about a year he will be joined by Prof. Pickering, who will probably remain two years, when it is hoped the work will be complete.