18 



Mr. AV. Johnston asked if it had not becii determined that a public 

 opening, followed by a conversazione, should take place, and that the 

 Governor was to be invited to officiate on the occasion as President of 

 the Society. 



The Secretary explained that nothing definite had been agreed 

 upon, but if a public opening were thought of, it would evidently be 

 better it should take place when the arrangements of the Museum 

 ■were complete throughout. Progress, however, was being made with 

 the Geological collection on the.upper floor. The Curator (Mr. Roblin) 

 had already arranged a complete and valuable series of specimens, 

 collected during the geological survey of Great Britain and Ireland, 

 which had been forwarded to the Society from the Government School 

 of Mines, Loudon, and with the assistance of Mr. M. Allport, and Mr. 

 Stephens, the remaining spvcimens would be classified with as little 

 delay as possible. lu the meantime as many enquiries were being 

 mafle as to the period of opening the Museum, it was thought better 

 that the public should at once be admitted to the portion already com- 

 pleted, than that further deiay should take place. 



Mr. Abbott remarked although a public openijig just now would be 

 impossible on account of the incomplete condition of the geological 

 museum, the present partial one would not preclude a mol-e formal 

 ceremony on a future occasion. 



Mr. Abbott then read a paper on the "Means which have been 

 adopted for ascertaining the velocity of light, and the Sun's distance ; 

 with especial reference to the forthcoming transit of Venus over the 

 Sun's dirc,in 1874, and 1882." After indicating the extreme importance 

 attached to this ev^nt by astronomers, Mr. Abbott alluded to the action 

 already taken in reference to it by scientific bodies in >^arious parts of 

 the world. An extract from an address by the Astronomer Royal of 

 England was read, specifying several stations at which observations 

 on the transit would be of peculiar value. Of these stations Tasmania 

 is one, but doubts are expressed as to whether the longitude [of this 

 place has yet been determined with the great accuracy which the 

 circumstancesof the case would require. Mr. Abbott hoped, however, 

 than Professor Airey would be satisfied on this point on receiving from 

 him a copy of the number of the Papers and Proceedings of this Society, 

 containing Captain Kay's account of the very elaboiate series of 

 observations, on which the longitude of Hobart Town was calculated. 



The Secretary after expressing his sense of the interest attached to 

 the paper just read observed it was evidently of great importance that 

 all those Governments who contemplated sending out observers to this 

 hemisphere should be well informed of the means taken to establish 

 with precision our exact longitude, and was certain thp council of the 

 Society would tase special care that the subject should be attended to. 



Mr. J. G. Crouch then, by means of the Gyroscope, exhibited some 

 interesting experiments, shewing how the principle ot gravity was 

 modified by rapid motion. In one of these a solid metal wheel or disk, 

 very thick at its periphery, 3i inches in diameter, and fixed on an 

 iron spindle, was made to revolve with exti'eme velocity. The spindle, 

 which was about 4 inches in length, being in a horizontal position, 

 a suspensory cord was then attached to one of its extremities in such 

 a manner that its rotation was not interfered with, and all other support 

 was removed. One end alone cf the spindle was now held up by the 

 cord, and the other projected at right angles to it, free and un- 

 supported in the air. In this singular position, in spite of its own 

 weight, and that of the wheel (1^ lb.) it continued to revolve as long 

 as its extreme velocity was maintained. The same was the case when 

 it was tilted up so as toformanangleof 40° with the • cord, and it was 

 only as the rotatory action of the wheel subsided that the distal ex- 

 tremity of the spindle gradually sank until the whole, suspended by 

 the cord, assumed the vertical condition. 



Mr. Facy, after alluding to the importance of Mr. Abbott's 



