'Did you see Hugo yesterday?' inquired Herr Groos of Franz, who was sitting next him.
'Yes, sir; I was there a long time. He wished he was coming with us.'
'Well, we all wish it too,' said the master heartily. 'What does he do with himself all day? Invent more cyphers?'
'No, sir, he does not mean to invent a new one,' answered Franz, laughing, 'till some one has solved the present one. I am to send him a long telegram in it every day.'
'What is that?' asked the short stranger, good-humouredly. 'I did not know there was such a thing as a cypher that could not be solved.'
'One of my pupils has invented one that no one has solved yet,' answered Herr Groos proudly.
'He should let me see it,' laughed the stranger. 'I would undertake to read it in half an hour.'
Then the master and the two strangers began to talk sociably together, and the conversation drifted to a discussion on the best place in the locality for the capture of butterflies, especially swallow-tails.
Franz listened attentively, for he was firmly resolved that he would not return without at least one specimen to adorn Hugo's collection. Herr Groos was of opinion that the Kühberg was the best place for them; but the strangers said, 'No, for every one found on the summit of the Kühberg there are at least three on the sunny slopes of the Hirsch-felsen on the opposite side of the valley.'
But at last the train journey came to an end, and the boys arrived at the little inn which was to be their head-quarters. There they were soon devouring rolls and hot coffee, almost faster than the inn-keeper and his good-tempered wife could bring them out of the kitchen. Then, with their pockets and knapsacks full of rolls and German sausage, they started on their first day's expedition to a little lake at the foot of the Kühberg. It was a lovely walk, and as they passed now under the cool green pine-trees, and now along sunny slopes where the cows, with their tinkling bells, were almost buried in sweet-scented flowers, both botanists and butterfly-hunters were busy. Finally, after two hours' walk, they reached their halting-place at the edge of the forest lake.