The attention of shipmasters is invited to the fact that it is very desirable to know the date when ice and other obstructions reported by radio from ship to ship were sighted. Many reports of this kind come to the Hydrographic Office bearing only the date of the radiogram and lacking the date when the obstruction was seen. Cooperation in supplying this additional fact will assist the work of this office and will be appreciated. SPECIAL SUBJECTS FOR INVESTIGATION The Hydrographic Office is pursuing the following special subjects of investigation and invites reports of the same from mariners: Port facilities, great sea waves, ocean currents, ocean routes, and value and correctness of charts. Information relative to and blanks for reporting the same can be obtained from the Hydrographic Office or its Branch Offices. [Chart top: No. 1400 Price 10 cents PILOT CHART OF THE NORTH ATLANTIC OCEAN Founded upon the researches made in the early part of the nineteenth century by Matthew Fontaine Maury, while serving as a lieutenant in the United States Navy. _Issued Monthly._ NOVEMBER, 1927] [Chart bottom: N. A.—NOVEMBER, 1927. Printed October 15, 1927 Prepared from data furnished by the HYDROGRAPHIC OFFICE of the NAVY DEPARTMENT and by the WEATHER BUREAU of the DEPARTMENT OF AGRICULTURE. [Legislative Act, June 17, 1910.] Published at the HYDROGRAPHIC OFFICE under the authority of the SECRETARY OF THE NAVY Washington, D. C. NOTE.—On the back of this chart will be found an article on “Fog at Sea.” Price 10 cents No. 1400] =1.= AVERAGE CONDITIONS OF WIND AND WEATHER OVER THE NORTH ATLANTIC OCEAN DURING NOVEMBER PRESSURE.—Pressure continues only moderately high along middle latitudes, but the crest to the southwestward of the Azores has increased to 30.15 inches. Off the coast of the United States the isobar of 30.10 inches extends farther eastward into the ocean than in October. A belt of moderately low pressure, 29.90 inches, extends in low latitudes across the ocean into the Caribbean Sea. The Iceland Low continues to deepen and the isobar of 29.70 inches appears in the position occupied by the 29.80 line of the previous month. TEMPERATURE.—The temperature has fallen 10° to 18° along the American coast and on the Gulf of Mexico except off central and southern Florida, and 3° to 8° over the British Isles and off western Europe. Elsewhere the changes have been unimportant. Sharp contrasts in temperature appear off the American coast, the temperature ranging from 30° in the Gulf of St. Lawrence to 75° at Key West. Along the northern trans-Atlantic routes the mean is from 45° to 55°. In the greater portion of the Caribbean Sea and east of it, between the 15th parallel and the Equator, the temperature is about 80°.