WE have to acknowledge the receipt from time to time of various communications from Mr. BALLINGALL, of Melbourne, New South Wales, on the subjects of unsafe ship-building, the causes of shipwrecks, &c.

Mr. BALLINGALL was, we believe, for- merly a Master in the Royal Navy, and has been for some years past employed at Mel- bourne as a Surveyor of Shipping. At Melbourne, he also holds the office of Honorary Secretary to the " Port Philip Immigration and Anti-Shipwreck Society." Mr. BALLINGALL'S communications have been chiefly copies of letters published by him in the ' Melbourne Argus' newspaper.

We have also recently received a pamphlet written by him, entitled " Unsafe Ship- building, a National Sin." Mr. BALLING ALL has for many years been the zealous advocate of an improved mode of building in the mercantile navy of this country, and especially of the intro- duction of solid bottoms, similar to those of men-of-war. He has also been an uncom- promising opponent of the system of Marine Insurance, to which he attributes a great part of the loss of lives and property from shipwreck, and maintains that its effect is to make it the interest of owners of ships to build cheap, unsafe, and ill-constructed vessels, rather than strong and safe, but somewhat more expensive ones. He, in- deed, goes so far as to state that he con- ceives even the Government of the country is interested in maintaining a system which annually occasions an immense sacrifice of life and property, since a large sum is brought into the revenue by the stamps on marine insurance policies; a sum which has amounted to as much as 300,00(M. in one year only.

Although we do not think it would be- come us to make so sweeping an onslaught as Mr. BALLINGALL has done on existing systems of so much importance, especially since much has been already effected in the right direction by the " Merchant Shipping Act of 1854," yet, doubtless, his arguments are worthy of some consideration.

Thus, no one can deny that a ship strongly built, having the spaces between the floor-timbers filled in with wood, and made water-tight, so as to form a thickness of 14 inches of solid wood—no one can doubt that such a ship would bear more thumping on a shoal or a lee-shore than a weakly-built one, having only 3 or 4 inches of planking between the floor-timbers; and no one can doubt that many instances would occur where the one would hold together after stranding until the falling of the tide, the subsidence of the gale, or the arrival of the life-boat should bring succour to her unfortunate inmates, whilst the other might break up, and be consigned to oblivion, with all on board her, within a few minutes of her striking the ground. How many an unhappy creature, in youth, or the prime of life, has, during out dark winter nights, yielded up his spirit in despair amidst the direful strife of the elements and the un- availing cries of his fellows in distress, who might, had his ship been built with a solid floor, have continued in the enjoyment of life, and gone down in peace to his grave, full of years and honour, and surrounded by all the comforts and consolations which love and friendship alone can provide! Again, although the system of marine insurance is calculated to prevent individual ruin and misery, by dividing losses at sea amongst a great number of persons, instead of their falling on single individuals, yet it cannot be denied that another effect of it may be to make those whose ships and cargoes are insured to their full value more indifferent to their safe preservation than they would be if great pecuniary loss, or, perhaps, actual ruin, were dependent on the safety of their property. Few men may be so hard-hearted as to deliberately wish the destruction of their vessels, careless of what might become of those who man them; but yet the first end which the followers of trade and commerce have in view is profit, which chiefly engrosses their attention ; and it is to be feared that, in too many instances, the provision of ample security to the lives of the masters and crews of their vessels occupies but a secondary place in their thoughts.

Upon the general question of marine insurance we will merely observe, that in our opinion a strict system of surveillance should be exercised, which would insure no unseaworthy, or ill-found, or half-manned vessel putting to sea; or else it should be made illegal for the owners of any ship or cargo to insure beyond half the value of the same, whereby his own pecuniary risk should indirectly afford that protection to the lives of the crew and passengers em- barked in his craft, which every British subject employed in a dangerous avocation should be entitled to.