found to possess. Its resistance to electricity is nmcli reduced 

 by the action of light ; a selenium pile being then interposed 

 in an electric circuit, and a beam of light of varying intensity 

 being made to fall upon it, the current is more or less resisted 

 in proportion to that intensity. The light is made to vary by 

 the effect of the voice in rendering the diaphragm of a tele- 

 phone more or less convex or concave, and thus sounds have 

 been reproduced at distances uj) to 800ft. It is not, however, 

 as a substitute for the ordinary telephone that this beautiful 

 instrument is likely to be of value, but for its applications in 

 rendering molecular vibrations audible wherever they occur, 

 opening up quite a new field of experimental research. It is 

 not necessary for me to enlarge on these subjects. The 

 sources of popular information on all these inventions are 

 numerous, and ample to satisfy curiosity ; what is rather 

 wanted, perhaps, is the curiosity itself. I mean an active- 

 minded interest in such subjects, to be created by systematic 

 instruction ; and here I must remark that I much approved 

 of a suggestion that one of the Tasmanian Scholarships 

 should occasionally be awarded to attainments in mathematics 

 and physics, with only a pass qualification in classics, if we 

 cannot afford to add to their number. Competent teachers 

 would soon be forthcoming. From such students the colony 

 would in time be furnished with mining, telegraph, and other 

 engineers, surveyors of a high class^ well-educated men, in 

 fact, in many departments of applied science, for whom it 

 must have a demand, as its industries develop, and who are 

 not turned out from existing schools. 



Mr. CrooJce's Researches. — At the risk of exhausting your 

 patience, I must allude to one other field of new research, 

 appealing to the imagination, and amazing the spectator more 

 perhaps than telephones or photophones, — I mean Mr. William 

 Crooke's researches* into what he has denominated the ultra- 

 gaseous state of matter. That an absolute vacuum is a thing 

 no art or apparatus can produce, is of course acknowledged. 

 What must then happen when something so near a vacuum 

 is produced that the gaseous pressure within a glass vessel is 

 reduced to a few thousandths of an inch ? It follows that 

 the atoms still remaining will disperse, and fill the whole 

 space, not of necessity at equal distances, but at greatly 

 augmented distances from each other. The denser they may 

 be in any one part — as where they are attracted to the walls 

 of the enclosure — the sparser must they be in other parts. 

 These invisible atoms, moving among themselves at incon- 

 ceivable velocities, can be made to manifest their pressure to 

 the eye : and as a skilful blacksmith can heat a rod of iron 



* Vol. 30, Proc. E. Soc, 1879, p. 469. 



