We have, fortunately, something else to do than to answer the wretched calumniator. We consider it our bounden duty, in so far as we can, to recommend to our readers the exceedingly able and temperate work of Sir Francis Head, which not only embraces all that can be said upon the topic in the way of abstract argument, but exhibits in the clearest form, and from the most authentic sources, the amount of foreign military and naval preparation, at the present moment, as contrasted with our own. It is, we think, a most timely and needful warning, which every one will do well to consider, not in a rash or hasty manner, but calmly, deliberately, and dispassionately, with reference to his own individual interests, and to those of the nation at large. The question, as it now presents itself to our notice, is not one of peace or war. The most zealous peace-monger alive need not be ashamed of adopting the conclusions or seconding the suggestions of the writer. The question, as put by Sir Francis Head, is simply this,--Are we, or are we not, supposing us to become involved in hostilities with France, in a condition successfully to resist all attempts at invasion? Of course there are several considerations collateral and connected with this. Military and naval establishments being, in effect, the insurance which we pay against the risk of invasion, the risk must be calculated in order to ascertain the amount. Only in one respect the parallel does not hold good between national and private insurance. A man may insure his premises or his life inadequately, and yet he or his representatives will be entitled to recover something. In the case of a nation, inadequate insurance is really equivalent to none. Either the insurance is good altogether, and fully adequate to the risk, or it need not have been effected at all. Therefore, in estimating this matter of sufficiency of defence, we must attempt to ascertain, as clearly as can be done by human foresight, aided by past experience, the amount of possible danger. This is unquestionably a most intricate consideration, yet no one can deny its importance.