Commissioner of Public Works to Commissioner of Police - "Proposed Illuminated Sign -  Chekiang & Hupeh Roads - -Cad. Lot 520, Central District". Shanghai, April 6, 1926. Source: SMA (SMC), U1-14-3266 (0990). 

An application for permission to erect an illuminated screen changing picture sign on the above lot and facing Nanking Road has been received from D.W. Hartigan on behalf of the Illuminated Advertising Company. If you are agreeable that this permit be issued I would suggest that a clause be inserted on the permit to the effect that permission may be withdrawn at one month's notice to the applicant.  

Commissioner of Police to Commissioner of Public Works - "Proposed Illuminated Sign -  Chekiang & Hupeh Roads Corner". Shanghai, April 9, 1926. Source: SMA (SMC), U1-14-3266 (0991). 

Reference to your No. B-63/827 of April 6, there are no police objections to the issue of the desired permit, but the permit should I think be liable to cancellation at any time, should in the opinion of the Police serious obstruction to traffic result.