“Survey of Egypt”

Data:

• 10” Rectilinear slide rule
• Paper scales A/B, C/D. No scales on rear of slide
• Incredible wooden box: the slide rule can not be removed without holding it upside down and tapping.
• “PD1” logo front and back
• On the back paper, “Survey of Egypt”
  Survey of Egypt (c. 1898 - present; مصلحة المساحة المصرية) was the official surveying body of the Egyptian government from the turn of the 20th century until the founding of the Republic of Egypt. As Egypt was a British Protectorate for most of this period, the survey closely resembled government survey operations in other British colonies and protectorates.
• Statement of the owner:
  “My own opinion at this stage is that it probably dates from the period immediately after the colonising politicians drew lines on large scale maps of Africa to divide it up between them. Then each of them sent out some poor devils to find out where these lines could actually be defined and agreed on the landscape. The information on the back includes a reference to imperial gallons but not to any other USA equivalent, but does give metric (European) equivalents when appropriate. Bear in mind that the USA was not involved in this particular political scramble.
  The “PD1” ‘logo’ appearing twice on the slide rule could be the signature of an ‘owning Department’, a maker's mark or a store's reference — or something else altogether! The sturdy box does not carry any mark at all and may not have been that supplied with the rule, but rather one made later and locally by someone who understood the operating conditions of aforesaid poor devils rather better than his remote masters. The design fault we commented on but the excellent craftsmanship may add credence to this idea.”

Questions:

1. Can anyone throw any light on this, either logo or whatever?
   “PD1” is probably a survey department designation. Siegfried Lion