306 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
visited the location and made suflicient measurements to enable him 
to convert the apparent distances given by the photographs into an- 
gles and linear distances; so that we are able to chart the position of 
the schooner and the waterspout from time to time during the twenty- 
five minutes embraced by the photographs. Three spouts were seen 
in succession, though it is probable that there was only one general 
whirl in the atmosphere, moving slowly southeastward while the 
spout cloud appeared and disappeared. No photographs of its first 
appearance were obtained, but those of the second and third appear- 
ances are published as half tones in the Monthly Weather Review 
for 1906 and are numbered as follows: 
Second appearance: 
A, 1.02 p. m., by Chamberlin at Cottage City. 
B, 1.03 p. m., by Coolidge at Cottage City. 
C, 1.08 p. m., by Hallet at Cottage City. 
D, 1.12 p. m., by Dodge at Vineyard Haven. 
Ki, 1.14 p. m., by Ward at Falmouth Heights. 
F, 1.17 p. m., by Coolidge at Cottage City. 
G, 1.17 p. m., by Coolidge at Cottage City. 
Third appearance: 
A, 1.20 p. m., by Chamberlin at Cottage City. 
B, 1.24 p. m., by Chamberlin at Cottage City. 
C, 1.27 p. m., by Coolidge at Cottage City. 
By reducing the measurements made on the photographs to lnear 
dimensions Professor Bigelow arrives at the following figures, which 
will interest you, because they are certainly the first that have ever 
been determined accurately for any waterspout: 
The diameter of the waterspout at sea level was 240 feet ; its smallest 
diameter midway between this and the cloud, 144 feet; at its summit, 
or the lower surface of the cloud, the diameter was 840 feet. The 
approximate length of the tube, or height from the ocean to the lower 
surface of the cloud, 3,600 feet. The height of the top of the cloud 
above its own base was 12,400 feet, and its total height above the ocean 
level was 16,000 feet. The spray, or cascade of drops forming a 
cloudy or smoky appearance at the base of the spout, was 720 feet in 
diameter, and the height of the summit of this cascade was 420 feet. 
As a small vessel is visible in the middle of some of these pictures, 
J will add that the distance from the photographic camera at Cottage 
City to the waterspout was 5.75 miles, but the distance to the schooner 
was only 2 miles; the movement of the waterspout from the north- 
west to the southeast was at the rate of about 1.10 miles per hour; the 
rate of the schooner was 1.7 miles per hour. The wind was very light 
at the time, as stated by several observers and as shown by the 
smoothness of the water. Meteorological observations are rather 
scanty, but from the best information at hand Professor Bigelow 
