Here is evidence, though not conclusive, of the immense force of gunpowder, and also of the progress of knowledge on the subject; yet it clearly shows the evil of coming to hasty conclusions, however well supported by apparent facts, as it has had in this case a tendency to check inquiry and retard the advancement of knowledge. For the extensive experiments of Hutton were but limited in discovery, because they were not carried to a sufficient extent, and thus, they are quite unsuited to the present day. He was satisfied because he had gone further than any of his predecessors; and though he established and clearly proved the soundness of his own theory, yet he could not either view the subject to its utmost bounds, nor yet go sufficiently far, but that others, taking up the question where he left it, may pursue the subject to a much more remote limit. The subject, indeed, was limited to him. He far excelled Robins, no doubt, as he has shown; but that involves no detraction from the merit due to Robins for his experiments and discoveries, no more than any individual proving the subject to be a more extensive one than Hutton did, would excel Hutton; for the value of improvement is more to be attributed to him who lays the foundation, than to him who raises the building. So is it in this case; Robins laid the foundation for an extensive knowledge of the nature and power of the explosive fluids, and Hutton built upon that foundation a certain extent of superstructure, and there he left it, without roofing the building: he considered the question as settled. Common consent has, as yet, received his conclusion as unshaken and uncontroverted; and it is not my intention to make the attempt to controvert it, but merely to show that his deductions fall short of what the principles of gunpowder-making admit--carried out in the more extensive way it has been within the last few years--owing to the limited nature of his experiments. This is rather an extensive position for me to occupy, or endeavour to hold: but I do not mean the size of the _tools_ of _experiment_ so much as the diversity of them; for exploding ten thousand tons of powder in the same machine and in the same way, would but give the same or similar results; it is the variety and the singularity of experiments that expand and increase the fund of knowledge, and enable the mind to conceive and comprehend the immensity of the power and velocity of this wonderful combination. We have been principally indebted to the exertions of the chemist for means of purifying and extracting from the ingredients which form this astonishing compound force, the impurities and foreign substances which exist, to a certain extent, in all the three, and thus tending to form a more perfect combustion by increasing the affinities.