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in analysing the gases which were produced by vegetation 
under water, and tinder the influence of solar rays, I made 
careful and repeated efforts with the object of detecting it, 
but failed to do so. I therefore suspect that this gas was the 
result of decomposition of some of the organic substances 
present in his experiments. 
A paper was read “ On an Apparatus for Measuring Tensile 
Strengths, especially of Fibres,” by Mr. Charles O’Neill, 
F.C.S. 
In the sketch, a is a cylindrical metallic vessel to hold 
water, and provided with a cock c. b is a hollow cylinder 
of glass or metal, closed at the lower end, and so weighted as 
to float vertically in stable equilibrium with a portion out of 
the water; upon its upper end a hook or clamp to hold the 
fibre is fixed. D is a fixed support, with another hook or 
clamp to hold the other end of the fibre, f is a lever with 
a long and short arm, the long arm passing over the scale 
g. h is the table or support, and e is a vessel into which 
water drawn from a is received. When using the apparatus 
it is nearly filled with water, and the fibre to be tested is 
properly secured to the fastenings on b and i), then drawn 
taut. Water is now allowed to flow slowly from c until the 
fibre breaks. The quantity of water drawn off is ascertained, 
and from it the strain put upon the fibre calculated. The 
indications of the long arm of the lever are also noted in 
order to show the stretch, and also to give the elements for a 
correction to be made upon the quantity of water drawn off. 
Stops and guides not shown in the sketch serve to keep 
the floating cylinder off the sides of the vessel, and prevent 
it falling too far upon the rupture of the fibre. 
