The nature of the angular distribution of the particles emitted in artificial transmutations is a matter which has received little attention. Hitherto experimental investigation has been mainly concentrated on the determination of the energy release and nature of various transmutations. But it is now clear that we have sufficiently precise data concerning the nature of many transmutations to make profitable their further investigation, and in particular the investigation of the angular distribution of the transmutation products. Moreover, in much of the literature it is implicitly assumed that the transmutation products are uniformly distributed in space when referred to relative coordinates,
i. e
., coordinates in which the centre of gravity of the system is considered to be at rest; in particular, all attempts to determine absolute yields depend upon the correctness of this assumption. The work so far published on this subject appears to support the uniformity of angular distribution, but further investigation is clearly of some importance. During the course of some cloud-chamber experiments on the transmutation
2
D +
2
D →
3
T +
1
H, (1) Dee formed the tentative opinion that the angular distribution of the protons emitted was not uniform. The alternative transmutation
2
D +
2
D →
3
He +
1
n
(2) is very similar to (1), since the spins of the particles are probably identical and the energy balances of the same order of magnitude. We have therefore investigated the angular distribution for both these transmutations.
Strength characteristic determination of a flat wagon carrying structure with a lower centre of gravity