4 KANSAS CITY REVIEW OF SCIENCE. 
Sibiriakoff has proposed to follow. The Nordenskjold was built at Malmo, 
Sweden, for the express purpose of going to the assistance of the explorer, whose 
whereabouts were then unknown. She was launched on April 23, 1879, and left 
Malta on June 3 for Behring’s Strait by way of the Suez Canal. She was to pass 
through Behring’s Strait and thence direct her course to the mouth of the Lena. - 
On August 4 the vessel left Yokohama and proceeded on her way north. At the 
time the Nordenskjold started it was considered that the Vega was beset in the ice 
some forty miles northwestward of East Cape at Behring’s Strait, and at a consid- 
erable distance from any settlement. The Nordenskjold was to seek the missing 
vessel there. When the fate of Professor Nordenskjold and his expedition were 
still undecided and grave fears were entertained for his safety, M. Sibiriakoff, a 
warm friend and supporter of the explorer, was the first to take practical measures 
for his relief and his steamer was the first fitted out for the purpose, he bearing all 
the expenses of the expedition. Not content with fitting out a steamer of his own, 
he made earnest appeals for assistance in all quarters where it was likely to be 
given. 
jevorl IOUN| CML, 
A NEW DETERMINATION OF THE DIAMETER OF MARS. 
H. S. PRITCHETT, ASTRONOMER MORRISON OBSERVATORY. 
During the near approach of the planet Mars, in the recent opposition of 
1879, the following careful observations of its diameter were made with the large 
Equatorial of the Morrison Observatory, partly with the purpose of testing the 
figure of the apparent disc, and partly to furnish an accurate measure with a filar 
micrometer for comparison with those obtained from the heliometer. I have just 
finished a reduction and discussion of these measures, and the results given below 
represent an abstract of a more complete paper forwarded to the ‘‘ Astronomische 
Nachrichten.” The observations were made by Prof. C. W. Pritchett. 
While the measures of such an object as the disc of Mars with a filar micro- 
meter, will never be entirely free from the effect of irradiation, and therefore will 
never give the true value of the diameter quite as accurately as the heliometer, 
still, in a telescope of such good definition as the one used, this effect would be 
very small. Filar micrometer determinations of the diameter are still further use- 
ful from the fact that they are to be used in the reduction of incomplete observa- 
tions made with similar instruments, and for other common astronomical opera- 
tions. For this reason the values of the diameters of planets used in computing 
their apparent discs for the Mautical Almanac, Berliner Vahrbuch and American 
LEiphemeris, are derived from observations with a filar micrometer. | 
