(Material collected at Canterbury and Belmore, localities a few miles from Sydney.)

In May and June, 1897, a somewhat similar investigation had been undertaken, in order to determine what variations were likely to occur in the character of the oils derived from trees of a species belonging to the "Gum" group of Eucalypts. The oils from the species of this group often contain the aldehyde aromadendral as a characteristic constituent, and it is present in that of this species.

1. Leaves and branchlets from a tree of fair size.

2. Leaves and branchlets from a large tree.

3. "Sucker" or abnormal leaves.

4. Leaves and branchlets from a large tree.

5. General material from old trees.

6. Leaves and branchlets from young trees 20 to 30 feet high.

7. General material from trees of medium size.

8. Leaves and branchlets from one tree of medium size.

9. Leaves and branchlets from a large tree, the material being divided into two parts and distilled separately. 10. Equal volumes of the above oils mixed together. Crude oils from the above material (1377 lb.) gave the following results: -

Colour of crude oil.

Yield per cent.

Specific gravity at 150 C.

Rotation ad.

Cineol, per cent. (O.M.)

1

Very light ..........

1.19

0.9207

+ 2.02°

60

2

Rather dark......

0.75

0.9157

+ 1.99°

50

3

Light........ .........

0.63

0.9184

+ 4.07°

54

4

Rather dark.... ......

0.88

0.9220

- 0.84°

51

5

,, ..........

0.75

0.9144

+ 1.25°

49

6

Light ........ .........

084

0.9179

+ 0.49°

64

7

Rather dark .......... .....

0.73

0.9181

+ 0.49°

58

8

Light ......... .........

0.66

0.9164

+ 0.60°

56

9

Dark...... ........

0.72

0.9129

- 2.30°

46

10

Light .......... .........

mean 0.79

0.9160

+ 0.85°

55

The laevo-rotation of Nos. 4 and g is due to the presence of a slightly larger amount of aromadendral than in the other samples.

The cineol was determined by the phosphoric acid method as carried out at that time, so that the amounts recorded in the table are naturally a little lower than would have been the case if the more modern methods had been adopted.

It will be observed that with Nos. 6 and 7, derived from general material, the characters were in close agreement, thus following the rule in this respect. The oil from abnormal leaves (No. 3) was of corresponding value, although it contained a little more pinene than that derived from older trees. Considering the results as a whole there was shown a fairly close agreement between the oils of the whole series, but identical results were only obtained with the two samples of oil from the same tree (No. 9).

The results of this investigation were published by us in the Proc. Roy. Soc, N.S.W., XXXI, 259.