656 
¢ 
relative length is quickly seized by the eye. When 
the subdivisions go down to one-degree squares, then 
tabulation is necessary to save space, if a variety of 
data is to be shown; but, on five-degree squares, we 
believe the general preference would be for graphic 
representation, unless, what would be still better, 
both methods were combined, somewhat as in Toyn- 
bee’s charts; but this would increase the size of the 
sheets. After all, the choice between the two methods 
must be made, not so much by the reviewer, as by the 
practical seaman, for whom the charts are especially 
constructed. 
Currents are not attempted on these charts: it is 
the intention of the hydrographic office to give them 
29.925 
ae 
4 
SCIENCE. 
[Vou. III., No. 69. 
ference of reading of one or two hundredths of an inch 
between the two. The broken and dotted lines are 
sea-water isotherms, with satisfactory coincidence. 
The arrows show the average winds: the only notable 
divergences are in the region of variables and calms. 
On attempting to draw out the isobars for the whole 
of our March chart, smooth curves can be traced up 
to latitude 30° or 35° by admitting corrections of two 
or three hundredths of aninch. Farther north, where 
observations are fewer, and barometric variations are 
known to be greater, corrections of five-hundredths or 
more are sometimes needed. This is probably due to 
the great difficulty of finding closely checked barom- 
eter records, especially in the older logs. Although 
Hig. 3. 
Special study as soon as possible, with particular 
attention to the temporary and local winds at the 
time of every observation. It may thus be possible 
to explain the rather discordant results shown on 
many current-charts. Before this, however, it is the 
desire of the office to complete the meteorological 
charts for the other oceans, on the plan now so well 
carried out for the North Atlantic. All who are in- 
terested in the success of this long piece of work will 
join in the wish that every aid and opportunity may 
be given to its progress. 
The accompanying figure (fig. 3) is inserted for 
comparison of these new charts with those of Toyn- 
bee’s squares that they cover, for the month of 
March. The full lines are isobars, the fainter ones 
being Toynbee’s. Their agreement in general atti- 
tude is good, but there appears to be a persistent dif- 
all defective records have been thrown out whenever 
detected, it is evident that some still remain; as, for 
example, in square 786, on the March sheet. We may 
therefore infer that the next improvement in the study 
of oceanic meteorology will come rather through in- 
creased accuracy than through increased number of 
observations. 
Another style of work undertaken by the hydro- 
graphic office is seen in the monthly Pilot charts of 
the North Atlantic, begun last December, of which 
mention has already been made in the columns of 
Science. These are designed to answer a double 
purpose, — first, to give a general representation of 
the prevailing winds for every month, based on the 
materials from which the more detailed meteoro- 
logical charts above described are constructed; and, 
second, to serve as a ready means of publishing the 
