-------------------------------------------------------------------------- Acid. | Formula. | Melting | Found in | | Point, | | | deg.C. | -------------------------------------------------------------------------- Tiglic | C_{4}H_{7}COOH | 64.5 | Croton oil. -------------------------------------------------------------------------- Moringic | C_{14}H_{27}COOH | 0 | Ben oil. -------------------------------------------------------------------------- Physetoleic | C_{15}H_{29}COOH | 30 | Sperm oil. -------------------------------------------------------------------------- Hypogaeic | C_{15}H_{29}COOH | 33 | Arachis and maize oils. -------------------------------------------------------------------------- Oleic | C_{17}H_{33}COOH | 14 | Most oils and fats. -------------------------------------------------------------------------- Rapic | C_{17}H_{33}COOH | ... | Rape oil. -------------------------------------------------------------------------- Doeglic | C_{18}H_{35}COOH | ... | Bottle-nose oil. -------------------------------------------------------------------------- Erucic | C_{21}H_{41}COOH | 34 | Mustard oils, marine animal | | | oils, rape oil. -------------------------------------------------------------------------- The unsaturated nature of these acids renders their behaviour with various reagents entirely different from that of the preceding series. Thus, they readily combine with bromine or iodine to form addition compounds, and the lower members of the series are at once reduced, on treatment with sodium amalgam in alkaline solution, to the corresponding saturated acids of Series I. Unfortunately, this reaction does not apply to the higher acids such as oleic acid, but as the conversion of the latter into solid acids is a matter of some technical importance from the point of view of the candle-maker, a number of attempts have been made to effect this by other methods. De Wilde and Reychler have shown that by heating oleic acid with 1 per cent. of iodine in autoclaves up to 270 deg.-280 deg. C., about 70 per cent. is converted into stearic acid, and Zuerer has devised (German Patent 62,407) a process whereby the oleic acid is first converted by the action of chlorine into the dichloride, which is then reduced with nascent hydrogen. More recently Norman has secured a patent (English Patent 1,515, 1903) for the conversion of unsaturated fatty acids of Series II. into the saturated compounds of Series I., by reduction with hydrogen or water-gas in the presence of finely divided nickel, cobalt or iron. It is claimed that by this method oleic acid is completely transformed into stearic acid, and that the melting point of tallow fatty acids is raised thereby about 12 deg. C.