MR SEVERN'S SECOND LECTURE.

Thames Star, Volume VII, Issue 2020, 25 June 1875, Page 2

MR SEVERN'S SECOND LECTURE.

The second of. Mr IT. A. Severn's course of lectures on " Light" was delivered in the Academy of Music last night. Commencing with a retrospect of the ground gone over -in the previous lecture, Mr Severn proceeded' to the velocity of light, and explained the means by which• the conclusions regarding the rate at which light jiravels had -been arrived at; illustrating the same by an experiment with a mechanical contrivance showing the .revolution of the planet Jupiter and his moons; by observing which-a Danish philosopher had made some wonderful discoveries. Mr Severn then proceeeded to still further reveal the wonders of the _ spectrum, showing how Bunsen and Kickeroff,' two' German scientists, while experimenting ; with a lantern and--spectrum had-accidentally discovered that certain minerals whilo being fused in- 1 the lantern presented different lines on tho spectrum. The illustrations in this portion of tho lecture wer* materially assisted by a solar spectrum slide showing, the lines referred to at the -previous lecture.' Further illustrations were afforded of tho causes of refraction, by means of a piece of plate glass placed across tho white streak thrown by< tho lantern 'without the interposition of the prism. A number of continental view's were. shown, also some very beautiful views ,bf~the moon, lunar Alps, craters, and'other-objects on tho moon's silvfaco o"s revealed by the aid of photography. Sonic local views wore al-o exhibited, and a portrait of a Maori was thrown out on the canvas screen very boldly. A microscopic lens |was then lixed to the lantern, aud sections of a vine

stalk and a cane magnified to an incredible extent. A flea,- some butterflies' wings, and the head of a moth with its antenna?, were also exhibited, and these illustratiens appeared to give great satisfaction. Mr Severn announced that on' the occasion of the next lecture he would use tho electrical light in the lantern, bis powerful battery to be employed ; when decomposition of water, formation of crystals and other interesting experiments will be exhibited. Thore was a capital attendance, Sir George Grey being present, and the lecture was listened to with marked attention.