(For the Scientific American.) In the “Scientific American,” of the 6th inst., R. G., complains of neglect of duty of the Steamboat Inspectors of New York in not inspecting ferry-boats, &c. If the writer had read the new Steamboat Law with any attention, he would have seen that by the 42nd section it is provided " that this act shall not apply to vessels ot the United States, nor to vessels of other countries, nor to steamers used as ferry-boats, tugging boats, or vessels under 150 tons, navigating canals." In your remarks you seem to have fallen into the same error. My object is to correct you, and at the same time to say these vessels should undoubtedly have been subjected to the law, for there is as much danger to life upon ferry-boats and canal passenger boats as upon any other class whatever. I was in Washington at the time of the passage of the law, and although it was the desire of the tramers of the bill to include these vessels, yet it was considered impossible to get it through the House, and even extremely doubtful if any bill would pass owing to the great opposition of Mr. Vanderbilt and others, and they were forced to take the law in its present shape rather than none. At this session of Congress, however, these vessels by all means should be included in the law, and it is hoped they will not be passed over. I feel some little pride in alluding to the success of the new law, and having devoted considerable time and attention in its passage, and as I thought had been somewhat instrumental in spreading correct information before the public, as to the cause of explosions and the proper remedies to prevent them, I cannot but look back with pride at the good results upon its provisions. If you will look at the facts in the case, taking for example the Mississippi River and all its tributaries, I believe you will find that from the 1st of January, when the law took effect, to this time, there has not been the loss of life of a single passenger, or even an injury to one, upon all these waters, whilst in the seven months of 1852, corresponding to these, there were over 50T persons killed. Taking the explosions and accidents elsewhere in the United States for the same period, they scarcely amount to anything in comparison with the loss before. With the exception of the explosion in California and Texas, I am not aware of but one instance in our whole territory where passengers have lost their lives. The great cause of complaint, it seems to ne, is the making this law a matter of poli-ics. As I ever understood it, this was a law lemanded by the necessities of the occasion ind for the benefit of the whole American jeople; it was for the security of life, not ior ihe aggrandisement of party. I do not be-ieve there was, during the passage of the bill :hrough Congress, one single voice in favor of ever making this a political question, in fact, Whigs, Democrats, and all others, were united n this question, and publicly and privately lisavowed any intention of the kind. The ate President acted upon this principle in ;he appointment of Supervising Inspectors, yet the " powers that be " have already removed some of the most deserving and filled their places with those who have no kind of knowledge of the business over which they are to exert such an important influence. In the 8th and 9th Districts neither of the Supervising Inspectors, it is said, can go on board of a steamer and stop the engines to save their lives. An Engineer.