Smoke, colored mortar shells

In May 1944 the Commanding General, South Pacific Area, asked for colored smoke mortar shells. Chemists developed mixtures containing dyes that produced red, yellow, green, and violet smokes. With a fiize set for an air burst, shells containing these smokes erupted a colored cloud visible for some miles and lasting for several minutes in calm weather. Colored smoke shells were recommended for standardization shortly before the end of the war. ... 

The difficulties the CWS faced in finding suitable smoke mixtures for grenades were duplicated in the work on colored artillery shells, mortar shells, roekets, and bombs. Chemists had to formulate mixtures that would release smoke of the desired density for the required time, and engineers had to cope with mechanical obstacles that appeared in casings. Artillery shells posed no unusual problem. Technicians took a base-ejection shell... 

During the period from 1920 to 1940 the CWS initiated approximately 700 projects for the Army, the Navy, and for civilian organizations. The military subjects encompassed gas masks, protective clothing, protective ointments, incendiary materials, mortars, airplane spray tanks, chemical cylinders, chemical artillery shells, colored smoke, chemical grenades, toxicological studies, meteorology, analytical methods, pilot plants, full-scale plants, filling plants, and medical studies. 

CWTC Item 105 2, Military Requirement and Military Characteristics for 4.2-Inch Chemical Mortar Colored Smoke Shell, 7 Jul 44. (2) Leo Finkelstein, Colored Smokes, vol. 12, 1 May 48, monograph in series. History of Research and Development of the CWS (1 July 1940-31 December 1945), pp. 91-94. 

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