IxX REPORT — 1876. 



not by cold calculations of this kind that great discoveries are made or great 

 enterprises achieved. There is an inward and irrepressible imiJiilse — in indi- 

 viduals called a spirit of adventure, in nations a spirit of enterprise — which 

 impels mankind forward to explore every part of the world we inhabit, 

 however inhospitable or difiicult of access ; and if the country claiming the 

 foremost place among maritime nations shrink from an undertaking because 

 it is perilous, other countries will not be slow to seize the post of honour. If 

 it be possible for man to reach the poles of the earth, whether north or south, 

 the feat must sooner or later be accomplished ; and the country of the success- 

 ful adventurers will be thereby raised in the scale of nations. 



The passage of Venus over the sun's disk is an event which cannot be 

 passed over without notice, although many of the circumstances connected 

 vrith it have already become historical. It was to observe this rare astro- 

 nomical phenomenon, on the occasion of its former occurrence iu 1769, that 

 Captain Cook's memorable voyage to the Pacific was undertaken, in the 

 course of which he explored the coast of New South Wales, and added that 

 great country to the possessions of the British Crown. 



As the transit of Venus gives the most exact method of calculating the 

 distance of the earth from the sun, extensive preparations were made on the 

 last occasion for observing it at selected stations — from Siberia in northern, 

 to Kerguclen's Land in southern latitudes. The great maritime powers vied 

 "^^dth each other to turn the opportuuity to the best account; and Lord 

 Lindsay had the spirit to equip, at his own expense, the most complete ex- 

 pedition which left the shores of this country. Some of the most valuable 

 stations iu southern latitudes were desert islands, rarely free from mist or 

 tempest, and without harbours or shelter of any kind. The landing of the 

 instruments was in many cases attended with great diihculty and even per- 

 sonal risk. Photography lent its aid to record automatically the progress of 

 the transit ; and M. Janssen contrived a revolving plate, by means of which 

 IVom fifty to sixty images of the edge of the sun could be taken at short 

 intervals during the critical periods of the phenomenon. 



The observations of il. Janssen at Nagasaki, in Japan, were of special 

 interest. Looking through a violet-blue glass he saw Ycnus, two or three 

 minutes before the transit began, having the appearance of a pale round spot 

 near the edge of the sun. Immediately after contact the segment of tho 

 planet's disk, as seen en the face of the sun, formed with what remained of 

 this spot a complete circle. The pale spot when first seen was, in short, a 

 partial eclipse of the solar corona, which was thus proved beyond dispute to 

 be a luminous atmosphere surrounding the sun. Indications were at the 

 same time obtained of the existence of an atmosphere around Tonus. 



The mean distance of the earth from the sun was long supposed to have 

 been fixed within a very small limit of error at about 95,000,000 miles. 

 The accuracy of this number had already been called in question on thco- 



