The Red Sea is comparatively unknown to navigators. It contains hidden rocks which must be charted and buoyed before its navigation can be rendered safe. Surely this ought not to take the world by surprise. As to the canal itself, we are only surprised that it has reached its present state of perfection and we advise those who now make haste to prophesy ignominious defeat for one of the greatest enterprises of the century, to suspend judgment for a time. New York journalists might certainly call to mind with profit, the annual troubles attending the opening of the canals in this State. Frosts heave and rats undermine, and banks annually give way, yet these things are not regarded as surprising. But upon the opening of a work, to which all the minor canals in the world are like the rods of the magicians to Aaron's rod which swallowed them up, it is expected that everything shall move without difficulty, and that no oversight will have been committed. Truly this would be to attribute a power of prevision to M. Lesseps beyond what is human. The world can afford to wait a little till this huge machine gets oiled. Great enterprises move slow at the outset. We have yet unshaken faith in the ultimate success of the Suez Canal. * * * * * TUBULAR BOILERS AND BOILER EXPLOSIONS. In our description of the novel steam boiler, published on page 209, last volume, we made a quotation from several eminent writers and experimenters on the subjects of heat and steam, to the effect that the tubular system in steam boilers was wrong in theory and unsafe in practice, and although this system has hitherto been extensively used on account of some advantages which it secures, it has long been a serious question with thinking men whether these advantages were not obtained at too dear a rate. While not prepared to admit all the force of the objections made to the tubular system, there are arguments against it that it will not do to treat lightly and which seem to us more and more forcible the more we candidly reflect upon the subject. One of the most forcible of these which occurs to us is, that in the tubular system the disruptive force of unequal expansion is far more likely to become a cause of danger than in the plain cylinder boiler. In such boilers the tension of expanded tubes is transmitted to the shell, which are greatly strained without doubt, often nearly to the verge of rupture. When this occurs it is evident an unusual strain, caused by sudden generation of steam, would act in concert with the expansion of the tubes, and we have no doubt these causes combined have given rise to many an explosion when the steam, acting singly, could never have produced rupture.