Page:Popular Science Monthly Volume 33.djvu/105

Rh could not be heard through the air, yet could be with fair distinctness through the telephone.

It is to be hoped that Prof. Blake may find opportunity to continue his experiments, as he seems to be on the verge of producing a practical and accurate instrument of value to mariners.

Methods of using the Morse code of dots and dashes, as represented by long and short sounds of a fog-whistle or other similar contrivance, have been made public. The best one I have met is that of Mr. Frank Purinton, of Providence, R. I., and it is one of the best because it is the simplest. The idea is that, when two ships meet in fog and make known their proximity to each other by their fog-signals, each shall indicate to the other the way she is steering by the length and the intermission of the sounds made by her fog-signal. The following is the code in part, the long blast being represented by the [—] dash, the short one by the [&bull;] dot:

The thirty-two points of the compass are represented by variations of the collocations of dots and dashes on the chart, and with long and short sounds with intervals, in practice. These signals can be given by the ordinary steam-whistle or by automatic apparatus already invented and in use. Mr. Purinton claims that his system will, if followed, prevent collisions. The four cardinal points of the compass are so represented that opposite courses have opposite signals. One long sound means north; a short one, south. Two long sounds mean east, and two short ones mean west. Other points of the compass are indicated by the synthesis or natural combination made by adding the necessary cardinal signals for the intermediate points or courses.

Another device, which may be called the echo-maker, that of Mr. De la Torre, has been examined by a board of naval officers, of which Commander Bainbridge Hoff, United States Navy, was the head, and report was made to the Navy Department of a somewhat favorable nature. It may consist of a flaring funnel screwed on the muzzle of a rifle. It is operated by firing the rifle in the direction of the supposed obstacle, such as a rock, an iceberg, another ship, or a cliff. If the obstacle is there, the