Under these circumstances advance was trying. The top-soil was as hard as rock, and could not be displaced except by dynamite, so that in the deep cuttings in mid-summer it was just as arduous to cut a way through the frozen loam as through the solid rock. The rivers, although they flow with a fierce velocity, freeze up quickly, and the ice assumes a great depth--a train can cross on the congealed surface with perfect safety. In this country, strange to say, it was found to be easier to work during the winter, notwithstanding the extreme cold, than during the summer, for a higher rate of advance could be maintained when the country was frost-bound. There is an almost total absence of snow, but, on the other hand, during the summer the rainfall is tremendous. The wet season lasts continuously for nearly two months--from the middle of June to the middle of August. The downpour is so terrific that floods are precipitated on every hand, and the resultant situation, as may be surmised, is of the most miserable character. In 1897 the effect of this deluge was experienced to an abnormal degree, for several villages were overwhelmed, and widespread misery was inflicted among the peasants. The railway did not escape, for large stretches of line were washed away and large quantities of material were lost. The scarcity of labour was felt very severely. Sufficient men could not be recruited locally, and to import navvies from Europe was hopeless. To meet this contingency the Administration authorities sanctioned the employment of exiles, while criminals were requisitioned to build the grade under a military guard. Though recourse to prison labour has been often advocated for railway construction, this is one of the rare instances where it has been brought into actual application through absolute force of circumstances. Assistance was rendered by Chinese labourers, and though at first they proved indifferent in the manipulation of tools, their assistance ultimately proved invaluable, as the majority developed into expert workmen.