63 
well worth while to test, for if proved it would completely 
re-establish confidence in the strength of the guns, which has 
been somewhat rudely shaken. 
Let a 12-inch gun be loaded with a double charge of pow- 
der and a double charge of shot, or a shot of double weight, 
and fired. If, as is probable, the gun does not burst, confi- 
dence in the gun will be re-established. Then let it be 
loaded twice over with the powder between the shot so as 
to ascertain whether the action of the powder when fired by 
percussion would not produce an effect similar to that which 
we are here considering. The destruction of one gun for 
the purpose of establishing confidence in all the rest would 
not seem to be an unworthy sacrifice. 
PHYSICAL AND MATHEMATICAL SECTION. 
January 28th, 1879. 
E. W. Binney, F.R.S., F.G.S., in the Chair. 
Dr. Bottomley called the attention of the Section to an 
interesting copy of the Principia of Newton. In addition 
to being an impression of the first edition it contains the 
autograph of Edmund Halley. It was a present from Halley 
to the Abbot Nazari. 
Nazari was the editor of a scientific journal at Rome from 
