From this extract it is evident that Professor Frank has undermined his own case. Belgian neutrality was intended by the great powers to be the corner-stone of the European balance of power. During the last forty years Germany's carefully meditated increase of armaments on land and sea threatened to dislodge the corner-stone. When the Conference of London declared Belgium to be a permanently neutral country, there was apparent equality of power on each side of the stone. In 1870 the Franco-German war showed that the balance of power was already disturbed at this corner of the European edifice. Still Germany's pledged word was considered sufficient guarantee of the _status quo_. Since 1870 the potential energy on the German side of the corner-stone has increased in an unprecedented degree, and this huge energy has been consistently converted into concrete military and naval forces. This alteration in the potential _status quo ante_ has been partly the result of natural growth, but in a still greater degree, to Germany's doctrine that it is only might which counts. Another German professor[138] had defined the position in a sentence: "Germany is a boiler charged to danger-point with potential energy. In such a case is it a sound policy to try to avert the possibility of an explosion by screwing down all its safety-valves?" Recognizing that Belgian neutrality has existed for many years past solely on Germany's good-will, it became the right and urgent duty of the other signatory powers to endeavour to strengthen the corner-stone. Germany absolutely refused to relax in any way the pressure which her "potential energy" was exercising at this point, therefore it was necessary above all for France and Great Britain to bolster up the threatened corner. [Footnote 138: Hermann Oncken (Heidelberg), in the _Quarterly Review_, October, 1913. The author of the article charges Great Britain with screwing down the valves, which is a deliberate distortion of the truth. Britain has always opened her markets free to German goods and admitted the same privileges to her rival--so far as these did not run contrary to established rights--in all parts of the world. With regard to territorial expansion a treaty had been drawn up between the two Powers and was ready to be signed just when war broke out. That treaty would have afforded Germany immense opportunities for expansion, but not at the expense of Europe. Germany, however, desired European expansion, and according to her accepted teaching, the fate of extra-European territories will be decided on the battlefields of Europe.] The former Power could have achieved this purpose by building a chain of huge fortresses along her Belgian frontier. Why this precautionary measure was never taken is difficult to surmise, but had it been taken, Germany would have ascribed to her neighbour plans of aggression--and declared war.