A farmer who is troubled by a winding stream passing through his land, cutting it up into awkward shapes, can straighten it by blasting a ditch across a loop in the manner just described. In the case of low-lying land, however, ditches are obviously no use, since water would not flow away along them. In that case the principle suggested just now for dealing with an inconvenient pond can sometimes be used, for if the subsoil be blasted through at several points it is very likely that water will find a way downwards by some means or other.
And the list of possible uses is by no means exhausted yet. A man opening up virgin land often finds old tree stumps his greatest bother. He can dig round them and then pull them out with a team of horses, but by far the simpler way is with a few well-placed dynamite cartridges, for they not only throw up the stump for him, but they break it up, shake the earth from it, and leave it ready for him to cart away or to burn.
Boulders, too, can be blown to pieces far more easily than one would think. The charges may be put underneath them as with the tree stumps, but in many cases that is not necessary, all that is needed being some dynamite laid upon the top of the rock and covered with a heap of clay. So sudden is the action of the explosive that its shock will break up the stone underneath it. Yet another way, perhaps the most effective of all, is to drill a hole into the stone and fire a charge inside it. It behoves the onlooker then to keep away, for the fragments may be thrown three or four hundred feet, a fair proof that the stone will be very thoroughly demolished.
Even in the digging of wells explosives may be useful. In that case the holes are made in a circle, and they slant downwards and inwards, so that their lower ends tend to meet. The result of simultaneously exploding the charges in these holes is to cut out a conical hole a little larger in size than the ring and a little deeper than the point at which the explosion took place. The bottom of that hole can be levelled a little and the operation repeated, and so stage by stage the well will proceed to grow downwards.
The thought that naturally occurs to one is this. All the operations described may be very well, the cost may be low, and the effect good, but are they sufficient to compensate for the risks necessarily dependent upon the use of explosives? The doubt implied in that question, natural though it be, is based upon prejudice, with which we are all more or less afflicted. The art of making these explosive substances has been brought to such a pitch that with reasonable care there is no risk whatever. The greatest possible care is used in the factory to see that all explosives sent out are what they are meant to be, and that they can therefore be relied upon to behave according to programme and not to play any tricks. That is the first step, and what with competition between makers, Government inspection, and searching inquiry into the slightest accident, and the desire of each maker to keep up the credit of his name, it is safe to say that modern explosives may be relied upon to do their duty faithfully. The second step in the process of securing safety is that the powerful explosive, the one that does the work, is made very insensitive, so that it is really quite hard to explode it. With reasonable care, then, it will never go off by accident. On the other hand, the sensitive material, which is easy to "let off," is in very small quantities, so small that an accident with it would not, again with reasonable precautions, be a serious matter.
Fuse, too, is very reliable nowadays. The man who lights the fuse may be absolutely sure that he will have that time to get to a place of safety which corresponds to the length of fuse which he employs. With electrical firing, too, it is quite easy to arrange that the final electrical connection shall not be made until all are at a safe distance, so that a premature explosion is impossible.
In many of the cases described, the shock takes place almost entirely within the earth and there is very little debris thrown about.
Indeed the only danger which is to be feared with these operations is about on a par with that which every farm hand runs from the kick of a horse. Any careful, trustworthy man could be quite safely taught to do this work, and with the assistance of a labourer he could do all that is necessary. Given a fair amount of intelligence, too, he would take but little teaching. Altogether there is no doubt that the use of explosives is going to have a marked effect upon farming operations in the near future.