(click on pictures to enlarge)
All of thse are marked "Welsh Manufacturing Co., Providence, R.I."
Most of the Welshes you find are cheaply made flattops such as the five on the right, marked only on the metal cap. However, the four on the left are a little nicer, especially the red hard rubber pencil marked "Welsh" on the clip and the black and pearl torpedo shaped example (which bears the imprint on the back of the upper barrel).
Often in this site I refer to the "Welsh mechanism," which refers to the large tippped mechanism that fits over the barrel. Here's a close up of one out of the pencil. These were simply pushed into the end of a tube, so that the bell shaped piece welded to the spiral would be wedged inside. Turning the outer section, to which is welded the inner tube, advances the lead up and down
Welsh was a very prolific manufacturer of this style of pencil, and many unmarked examples are also attributed to the company.