Altitudes of thunderclouds vary. They may hover above the earth at 800 feet. They may be a mile high. They have been observed on peaks of mountains three miles high. Many other electrical phenomena are observed in the mountains. The study of these will undoubtedly benefit meteorology and perhaps go far to explain the unsolved problems of the Service. One kind of thunderstorm that is rather rare is that which arrives in winter with the passage of an energetic cyclone. Often when the wind, having been in the southeast for most of the storm, is passing around and reaches the south or southwest the rainfall culminates in a deluge and thunder is heard. One or two such storms are a winter's complement. They usually terminate the rainfall for that particular cyclone. I have never heard of damage caused by these winter electrical storms, and they occur only in exceptionally well-developed areas of low pressure. Lightning has many times been observed during heavy snow storms. I have never heard any thunder with it. The discharge must have been very faint. [Illustration: STRATUS _Courtesy of Richard F. Warren_ Stratus is merely lifted fog in a horizontal form, the lowest of all, and the simplest as regards structure. It means neither rain nor snow and the apparent clearness of the blue above it would indicate clear weather to come. But through the break in the stratus near the horizon shows a cloud of firmer texture, which is less reassuring. Stratus over the land in winter takes the appearance of long bolsters of gray through which a pale blue sky shines. Such clouds may blanket the sky for days without causing a drop of rain. If they show a tendency to glaze over expect snow or rain, but not in large quantities.] The fascination that a thunderstorm has for many people is explained partially by the fact that one sees the whole process from beginning to end. The officials of the Weather Bureau have this privilege as regards cyclones. It is their business and pleasure to watch the setting up of these vast storms, to follow them on their journey. It is small wonder then that they find the spectacle fascinating. THE TORNADO The birds, the flowers, and the tornadoes are all busiest in spring. And the tornadoes probably make the largest impression. A tornado is merely a whirl of air, caused, as are all the other whirls, by a striking difference in temperature in adjacent areas. A tornado is a local and restricted example of the same thing that a cyclone is. But a tornado rarely crosses more than a single state; a cyclone strides continents. A tornado lasts, in one place, about a minute; a cyclone affects the weather for three days. A tornado never survives the night; a cyclone plods on for a week. And yet if you are betting on destruction put your money on the tornado. What it lacks in the realms of space and time it makes up in intensity. Its sting is fatal.