PROFESSOR BLACK'S LECTURES.

Tuapeka Times, Volume XVIII, Issue 1168, 5 August 1885, Page 2

PROFESSOR BLACK'S LECTURES.

As previously announced, Professor Black delivered a couple of lectures on "Explosives" in the Trinity Church schoolroom. The first lecture on Monday evening dealt chiefly with explosive mix- 'i tures of gases. Unfortunately, the weather *^ was not at all propitious, the ground lying white with snow, and this interfered seriously with the attendance. Had it been anything like a fine night, a crowded attendance would have been certain. At it was, there was a fair attendance when all things are taken into account. The first experiment of the evening consisted of exploding a mixture of oxygen and hydrogen gases. These gases were placed in a jar in the proportion of two volumes of hydrogen to one of oxygen. Dr Black explained that these were the proportions in which the gases combined to form water. , On ; . applying a lighted splinter of wood to the mixture of gases they rushed together with a loud explosion, and formed water, the quantity of water produced exactly equalling the weight of gas exploded. The gases in the 'jar before applying tho light were merely a mixture of oxygen and hydrogen; by exploding them they formed a compound, and the strange thing was that this compound was water. He exploded a mixture of hydrogen gas in air ; but the explosion was not nearly so energetic, as the oxygen of the air was I largely diluted with an inert gas known ■•' j as nitrogen. Water was, as before, the ! product of the explosion. Fire-damp waß next exploded with oxygen and with air. It was explained that fire» damp and coal ga3 were similar compounds, containing both hydrogen and carbon in the gaseous state. Coil gas was also exploded along with oxygen and