Mr. Appleton happened to be in a very amiable mood when Bob broached the subject, and though he uttered doleful warnings and foretold broken limbs, and declared that he washed his hands of all responsibility, he told the boys that they might do as they pleased. Next day they invited volunteers from among the Kalmuck miners, and were somewhat surprised when Nurla Bai was the first to offer his services, explaining that he was an expert in carpentry. Taking this as a sign of grace, Bob engaged the man, and told him to choose his own assistant. Nurla at once suggested a dwarfish man named Tchigin, a thick-set, muscular fellow with a huge head covered with jet-black hair. Mr. Appleton called him Black Jack. They began work, and Bob was well pleased with their industry and skill. Before night there was a row of half-a-dozen of the smaller poles in position, and all was ready for the drilling of the larger hole for the first of the stout beams that were to support the wooden path.
On the subsequent days, with the number of workers increased to six, the work was carried on even more rapidly. The greatest difficulty encountered was a bend in the cliff a few yards before it opened out on to the ledge on which the aeroplane was to be put together. It cost a good deal of labour to shape the planks to the curve, and to fix the beams; and the boys regarded it as a further disadvantage that the ledge would be out of sight from the mine. Not that they could suppose that the aeroplane, when set up in its hangar there, would be in any danger of molestation, for the only approach was from the Pathan compound, and Mr. Appleton thought that the Pathans might be trusted. But they would have preferred that their flying machine should always be in sight. However, there came a time when they were very thankful for the projecting corner of the cliff which had given them so much extra toil.
Their proceedings naturally caused a good deal of curiosity and excitement among the miners and the domestic staff. No one was more deeply interested than Ditta Lal, who numbered among his many accomplishments a smattering of theoretical engineering picked up in the course of his studies at Calcutta University. He talked very learnedly of strains and stresses, and often laid before the boys scraps of paper on which he had worked out magnificent calculations and drawn elaborate diagrams for their guidance. This amused them at first, but it became rather exasperating as the work progressed. He had a formula for everything; taught them exactly, to the fraction of an inch, how far the timbers should project from the ends of those supporting them, and what strain each portion of the structure could bear. As the successive bridges were completed, he proved, as he supposed, the accuracy of his calculations by venturing his own portly person upon them, at first with some timidity, but with more and more confidence as time went on. Mr. Appleton, on the other hand, watched the work from the security of the compound until it passed from sight round the shoulder of the cliff.
"You're a heap braver than I am," he said once to Ditta Lal. "I wouldn't trust myself on the thing for a pension, and you're heavier by three or four stone."
"Ah, sir, conscience makes cowards of us all," replied the Babu; "by which I understand immortal bard to mean, ignorance makes you funky. With my knowledge of science, imbibed from fostering breast of Alma Mater, Calcutta University--of which, as you are aware, I have honour to be B.A.--I know to a T exact weight planks will support, all worked out by stunning formulæ, sir. Knowledge is power, sir."
"Well, if you quote proverbs at me, I'll give you one: 'A little knowledge is a dangerous thing.'"
"A thousand pardons, sir, and with due respect, you have made a bloomer: misquotation, sir. Divine bard wrote: 'A little learning is a dangerous thing;' and I understand him to mean, if even a little learning in a man is dangerous to critic who tries to bowl him out, how much more dangerous is a fat lot!"
Mr. Appleton found it necessary at this point to break away, and Ditta Lal's further exposition was lost.
One evening, when the work of the bridge makers was nearing completion, the accepted explanation of Pope's line was brought home to the Babu by a rather unpleasant experience. He had walked along the finished portion of the pathway, which consisted of two lines of stout and broad planks supported by the cantilevers, these resting on the thick beams firmly embedded in the rock. The workmen on their swinging platform, Nurla Bai and Black Jack, had just laid the planks forming one bridge section across the gap, and were about to knock off work for the day. Ditta Lal was so eager to prove the soundness of his calculations, and demonstrate the valuable share he believed himself to have had in this engineering feat, that he took it into his head to walk across the planks to the other side. He had sufficient caution to hold on to the rope which had been carried along the smaller poles just above the level of his head.
"Hi, Ditta Lal! Come back!" shouted Bob from behind him. "The planks aren't nailed down yet."