n. A collection of visible vapor, or watery particles, suspended in the upper atmosphere. A classification of clouds according to their chief forms was first proposed by the meteorologist Howard, and this is still substantially employed. The following varieties and sub varieties are recognized: (a) Cirrus. This is the most elevated of all the forms of clouds; is thin, long-drawn, sometimes looking like carded wool or hair, sometimes like a brush or room, sometimes in curl-like or fleece like patches. It is the cat's-tail of the sailor, and the mare's-tail of the landsman. (b) Cumulus. This form appears in large masses of a hemispherical form, or nearly so, above, but flat below, one often piled above another, forming great clouds, common in the summer, and presenting the appearance of gigantic mountains crowned with snow. It often affords rain and thunder gusts. (c) Stratus. This form appears in layers or bands extending horizontally. (d) Nimbus. This form is characterized by its uniform gray tint and ragged edges; it covers the sky in seasons of continued rain, as in easterly storms, and is the proper rain cloud. The name is sometimes used to denote a raining cumulus, or cumulostratus. (e) ...