hat a shame it is, Hugo, that when your father is giving the whole class this splendid treat in honour of your recovery, you yourself should be the only boy absent.'

Hugo laughed somewhat sadly. 'Yes, I should like to be going, but the doctor says that I must not walk much before Christmas, and no one wants to spend three days in the woods in the middle of December. I should have liked the chance of catching a swallow-tailed butterfly for my collection.'

'I will try and get one for you,' answered Franz, 'though they are scarce this year. But what is this? How did you get your medal back?' as he picked up a silver disc from the table.

Hugo had won this medal a year before for a Latin composition for boys under fifteen, and when Baron Rosenthal's beautiful collection of coins and antique silver had been stolen, the medal had gone too.

'A friend of Father's saw it in a Berlin curiosity show among a lot of coins, and he sent it back to me.'

'And the coins—were they also your father's?'

'He has gone to Berlin to look at them, and he will be back to-night. But all coins are not easy to recognise. If it had been any of the silver boxes or cups he would have known his own at once.'

'And none of these have been traced?'

'No, not one. My father thinks they have probably been sold in some foreign country—America, perhaps, or England. But see, he left this money for you, so that you can let me know what you are doing. Then you can send me a long cypher telegram every day from the station on the Observatory, and it will give me something to do to translate it,' and he handed Franz some silver.

During his illness, Hugo had occupied himself in inventing a most elaborate cypher, which was the envy of the whole school. Not even the masters could read it, and it was an endless source of amusement to himself and Franz, who alone was in the secret.

'All right!' answered Franz; 'I will send you three telegrams, and catch you three swallow-tails too if I can manage it.'

As he went out of the room, his school-fellow looked wistfully at the pair of crutches that stood beside his invalid's chair. He was the only son of a very rich German nobleman, and six months before he had been nearly killed in a railway accident. When he began to recover, the Baron had promised to give a special treat to his son's class in honour of the event, and now that the time for the annual excursion had arrived, he was paying all expenses for the boys to remain three days in the forest instead of, as was usual, only one. It is the custom in German schools for each master to take his class for a long day's expedition into the country during the summer, in which he is supposed to open their eyes to the beauties of nature and the wonders of the botanical world; and the Baron, who was a very wealthy man, had caused this privilege to be extended that year. But now his son was unable to enjoy it, and this use of telegrams was a suggestion of his father's to prevent his being too depressed by the thought of his disappointment.

At five o'clock on the following morning there was a very cheerful party of boys waiting at the station for the little hill-climbing train that was to take them into the heart of the Black Forest. The master, Herr Groos, was also in the best of spirits, in spite of his failure to make any of the boys listen while he explained to them how the train was enabled to climb a hill. The boys, with their yellow caps, which was the distinctive colour of their class, and their butterfly-nets, botanical presses, and green specimen-cases, were much too excited to listen to him.

At last the train arrived, and they all filed into an open third-class carriage, whose only other occupants were two strangers, a tall and a short one, also armed with butterfly-nets and enormous green cases.

'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.

(Continued on page 130.)