IT WAS NO MISUNDERSTANDING

I believe that this 'misunderstanding' of 1st August was a trick to give Germany confidence that Great Britain would stay out of the war (King George had told Prince Henry on 26th July that he hoped Great Britain would remain neutral) so that when the ultimatum that Germany gave to Russia on the 31st July expired on 1st August Germany would indeed declare war on Russia.

Here is how Lichnowsky, the German Ambassador to Great Britain, describes this 'misunderstanding':

Sir W. Tyrrell called on me on the morning of the 1st August to tell me that his chief still hoped to find a way out. Would we remain neutral if France did? I understood that we should then agree to spare France, but he had meant that we should remain altogether neutral-towards Russia also. That was the well-known ''misunderstanding.r Sir Edward had asked me to call in the afternoon. As he was at a meeting of the cabinet, he called me up on the telephone, Sir W. Tyrrell having hurried to him at once. In the afternoon, however, he talked about Belgian neutrality and the possibility that we and France might face one another in arms without attacking. This was thus not a proposal at all, but a question without any binding force, as our interview, as I had already reported, was to take place soon afterwards. Berlin, however, without waiting for the interview, made this report the foundation for far-reaching measures.

It's that question: "Would we remain neutral if France did?"

If Tyrrell/Grey meant towards Russia too then why didn't they explicitly mention Russia?

Because Russia was not mentioned by Tyrrell, Lichnowsky didn't mention Russia in his telegram to Berlin. The offer/question of neutrality of Great Britain sent Berlin into wild joy (for why would Great Britain ask such a question if it didn't mean it?), and so when the ultimatum to Russia expired Germany, given some confidence that Great Britain was going to remain neutral due to this offer/question of 1st August (and King George V had told Prince Henry that he hoped Great Britain would remain neutral), declared war on Russia.

WHAT A BUNCH OF FUCKING BASTARDS!!!