We have received several letters inquiring of us if we know anything about the firm of Cornwall Bros., who are advertising in the SCIENTIFIC AMERICAN a book upon the sale of patents. Complaint is made that letter oontaining remittances for it are not answered. In some instances blame has been imputed to us for permitting the advertisement to appear in our columns. Now in regard to the firm above mentioned, we know nothing more of it than what is contained in the advertisement, and if those who seek to cast censure upon us will but exercise a little reflection, they will see that we cannot possibly vouch for the character of all the advertisers who make use of our columns. The gentlemen referred to will no doubt be able to make a satisfactory explanation. The report of the building of the lighthouse off Belle Isle, Coast of France, and a statement of its stability by Leonor Fresnel, engineer of the works, has been translated and published for the benefit of the United States lighthouse service.