We present results of optical broad-band and narrow-band H \alpha observations of a sample of forty nearby early-type galaxies .
The majority of sample galaxies are known to have dust in various forms viz .
dust lanes , nuclear dust and patchy/filamentary dust .
A detailed study of dust was performed for 12 galaxies with prominent dust features .
The extinction curves for these galaxies run parallel to the Galactic extinction curve , implying that the properties of dust in these galaxies are similar to those of the Milky-Way .
The ratio of total to selective extinction ( R _ { V } ) varies between 2.1 to 3.8 , with an average of 2.9 \pm 0.2 , fairly close to its canonical value of 3.1 for our Galaxy .
The average relative grain size \frac { < a > } { a _ { Gal } } of dust particles in these galaxies turns out to be 1.01 \pm 0.2 , while dust mass estimated using optical extinction lies in the range \sim 10 ^ { 2 } to 10 ^ { 4 } M _ { \odot } .
The H \alpha emission was detected in 23 out of 29 galaxies imaged through narrow-band filters with the H \alpha luminosities in the range 10 ^ { 38 } - 10 ^ { 41 } erg sec ^ { -1 } .
The mass of the ionized gas is in the range \sim 10 ^ { 3 } - 10 ^ { 5 } M _ { \odot } .
The morphology and extent of ionized gas is found similar to those of dust , indicating possible coexistence of dust and ionized gas in these galaxies .
The absence of any apparent correlation between blue luminosity and normalized IRAS dust mass is suggestive of merger related origin of dust and gas in these galaxies .