The device was therefore adopted of keeping the minutes and seconds the same for all places right across the continent, but of changing the hour at every 15° of longitude. The question then arose what longitude should be adopted as the standard. The Americans might very naturally have taken their standard time from their great national observatory at Washington, or from that of their chief city, New York, or of their principal central city, Chicago. But, guided partly no doubt by a desire to have their standard times correspond directly to the longitudes of their maps, and partly from a desire to fall in, if possible, with some universal time scheme, if such could be brought forward, they fixed upon the meridian of Greenwich as their ultimate reference line, and defined their various hour standards as being exactly so many hours slow of Greenwich mean time. The decision of the United States and of Canada brought with it later a similar decision on the part of all the principal States of Europe; and Greenwich is not only 'Longitude Nought' for the bulk of the civilized world, but Greenwich mean time, increased or decreased by an exact number of hours or half-hours, is the standard time all over the planet. No; the statement requires correction. Two countries hold out, both close to our own doors. France, instead of adopting Greenwich time as such, adopts _Paris time less_ 9 m. 21 s. (that being the precise difference in longitude between the two national observatories). Ireland disdains even such a veiled surrender, and Dublin time is the only one recognized from the Hill of Howth to far Valentia. So the distressful country preserves her old grievance, that she does not even get her time until after England has been served. The alteration in national habits following on the adoption of this European system has had a very perceptible effect in some cases. Thus, Switzerland has adopted Mid-European time, one hour fast of Greenwich; the true local time for Berne being just half an hour later. The result of putting the working hours this thirty minutes earlier in the day has had such a noticeable effect on the consumption of gas, as to lead the gas company to contemplate agitating for a return to the old system. Thus, Greenwich time, as well as the Greenwich meridian, has practically been adopted the world over. It follows, then, that the determination of time is the most important duty of the Royal Observatory; and the Time Department, the one to which is entrusted the duty of determining, keeping, and distributing the time, calls for the first attention.