Thomas A. Edison was once reluctantly persuaded by his wife to attend one of the big social functions of the season in New York. At last the inventor managed to escape the crowd of people vying for his attention, and sat alone unnoticed in a corner. Edison kept looking at his watch with a resigned expression on his face. A friend edged near to him unnoticed and heard the inventor mutter to himself with a sigh, “If there were only a dog here!”