J 
52 Joty—On the Conservation of Mass. 
these experiments. It must be remembered, too, that the space-velocity used in the 
forecast of the greatest possible acceleration does not include that of the solar 
_ system. According to some authorities, after allowing for the high angle with the 
ecliptic made by the solar motion, the velocity as used should be increased, for 
the time of year at which the observations were made, nearly 50 per cent. 
To improve on the foregoing method of experiment the passage of heat out 
of, or into, the external envelope containing the vessels in which the reactions 
are taking place, might be further delayed by the use of a Dewar vacuum-jacket, 
employing very light-blown glass in its construction. The tube bearing the 
fusible plug might well be carried to a point beneath the centre of the beam, and 
there the radiator be located in a cell as far as possible cut off from the space 
holding the vessels. This space should be vacuous in order to reduce the mass 
of the convection currents, the vessels holding the reagents being, in such case, also 
partially exhausted. Less quantities of chemicals and smaller vessels, and, perhaps, 
a quartz suspension, would also be improvements. The observations should be 
extended to various reactions and changes of state of aggregation. So long as 
there was the possibility that a true weight-change had been detected by Herr 
Heydweiller, it appeared advisable to confine the experiments to substances which 
appeared to have yielded positive results. 
