The six Scandinavian societies held a picnic at Washington Heights yesterday. Nearly 5,000 persons were present and the affair was an unqualified success in every respect. Sargent Johnson and eight policemen were in attendance, but their presence was wholly unnecessary, for the Scandinavians, unlike the wild Irishmen, can have a good time without breaking heads; and unlike Hesing's crew, the Scandinavians do not think a violation of law necessary to enjoyment. The picnic party returned to the city about 8 o'clock last evening and were unanimous in voting their day a well-spent one.