Note 642 — VIII CONCLUSION

The concession of specially low rates for these classes of packets has given rise to a noteworthy general line of division between postal packets. All packets passing at privileged rates must obviously be subject to examination and check by the Post Office in order to ensure that the privilege is not abused, a necessity which leads immediately to the principle of the "open" post, as contrasted with the "closed" post, the ordinary sealed letter packet. The difference in charge is not, however, based on the consideration that the packets are open to inspection. The effect is in the reverse direction. The view of practical officers is that, other things being equal, the treatment of a packet sent by the Open Post is more expensive to the Post Office than its treatment if sent by Letter Post.

The requirement is imposed in order that compliance with other conditions may be ensured. In none of the five countries are ordinary letters allowed to pass at postcard rate if merely enclosed in open covers. But a printed circular letter, if sent in a sealed cover, would lose its claim to the privileged rate.