The air-pumps were capable of driving through the reduction chamber over 80,000,000 cubic inches, or 4,000 pounds of air in every twenty hours; but this vast amount yielded only 400 grains of ozone. The expenditure of force for the result obtained was enormous; but there was no other method for them to get the amount of ozone required, except with greater power and cost. Early in July, Cobb had gained the assistance of Colchis to manufacture these crystals, and had put in the reducer, pumps, and motor immediately after. Every evening at six o'clock, and every morning at five, a team drove up to Colchis' back gate, delivering new storage batteries and taking away the old ones. Day after day, from seven in the morning until five in the afternoon, and from seven in the afternoon until five in the morning, since the 5th of August, the manufacture had been going on; making one hundred and twelve days' work up to the morning in question--November 25, 1887. "Master, this is the 25th of August, is it not?" "Yes, Junius." "And you say the quantity that I asked for is nearly ready?" "Nearly. At five o'clock to-morrow morning I will have 45,000 grains." "Good! That is the amount, exactly." "But at first you desired only seven pounds; I would have had that some time ago." "Yes, master; but I did not care to have you stop at the exact amount; circumstances might cause me to wish for more, at the last moment." "It has been incessant work for the machines, I can assure you; but they have done splendidly;" and Colchis laid his hand lovingly upon the reducer, near which he was standing. "Colchis, how can I ever repay you for the time you have given to the manufacture of these crystals?" and Cobb took up a glass bottle with a sealed top containing a pound of ozone, the result of over two weeks' constant work. "Say nothing about pay, my dear boy; it has cost you enough already, I fear; for the continual recharging of all these accumulators must take no small sum." "True; it has taken quite a little fortune, to me at least, to obtain these eight pounds of ozone; but I hope the money has been well expended." "Junius," and Colchis laid his hand upon the other's shoulder, "you have never told me what you are going to do with all this ozone. Is there a secret about it? If there is, my boy, you need not say a word; perhaps I ought not to ask you, but leave you to tell me, or not, as you wish." [Illustration] "Colchis, my dear old friend, I ought to be more confiding, and tell you why I sought your assistance, why I have used your time, why I have taken your knowledge and used it to my own advantage; but it is impossible to make you acquainted with this one great object. Ask no more, I pray you!" and he turned away as if he had refused that which the other was justly entitled to request. Putting his arm about Cobb's neck, Colchis looked him in the eyes with a kind and loving expression: