We have received a communication from Wm. H. Lindsay, of this city, stating that the Steam Boiler Telegraph Alarm, which we saw in operation at the engineering works of Messrs. Pease Murphy, of this city, and which we noticed in our columns, is described in a patent granted to him in 1849. This patent Electro Magnetic Boiler Alarm, which we spoke ot, is described in O. Byrne's recent work as the invention of Arthur Dunn, now a resident of England, and in whose name the recent patent for Ericsson's engine was taken out iu London. He was formerly, we believe, a resident in this city, and has both an English and an American patent for the Electro-Magnetic Boiler Alarm. Mr. Lindsay's papers were filed in Washington, describing the Alarm on the 16th March, 1848 ; Arthur Dunn's were filed in England a month afterwards ; the coincidence, a somehow, is remarkable.