Running in Circles
by Nathan Fung
ANSWER: MECHANICAL IMPEDANCE / DEPUTY CHIEF ENGINEER
Each day's log consists of two pictures that have each been taken from a bridge in Boston. Each pair of bridges defines a running loop, the distance (in miles) of which are available online ([1], [2]) and replicated below:
The supplementary information from 1710 reveals that in the alternate history, the Charles River was diverted and the running loops distances were altered.
| Running loop (From) | Running loop (To) | Distance (Original) | Distance (Alternate) |
|---|---|---|---|
| North Beacon St Bridge | Longfellow Bridge | 13.21 | 13.0401 |
| Arsenal Bridge | John W Weeks Footbridge | 4.76 | 4.2506 |
| Harvard Bridge | Longfellow Bridge | 2.82 | 2.1521 |
| JFK Blvd / Anderson Memorial Bridge | Longfellow Bridge | 7.78 | 7.1820 |
| John W Weeks Footbridge | River St Bridge | 1.18 | 1.0505 |
| North Beacon St Bridge | Science Museum / Craigie Bridge | 14.16 | 14.1416 |
| Eliot Bridge | Longfellow Bridge | 9.23 | 9.1201 |
| John W Weeks Footbridge | BU / Cottage Farm Bridge | 3.35 | 3.1721 |
| JFK Blvd / Anderson Memorial Bridge | Western Ave Bridge | 1.3 | 1.0523 |
| Mt. Auburn / Watertown Bridge | BU / Cottage Farm Bridge | 12.32 | 12.0912 |
| Mt. Auburn / Watertown Bridge | John W Weeks Footbridge | 9.18 | 9.1209 |
| Arsenal Bridge | Science Museum / Craigie Bridge | 12.66 | 12.0113 |
| Mt. Auburn / Watertown Bridge | Longfellow Bridge | 16.13 | 16.0102 |
| John W Weeks Footbridge | Harvard Bridge | 5.11 | 5.0912 |
| Harvard Bridge | Science Museum / Craigie Bridge | 3.77 | 3.1209 |
| Western Ave Bridge | River St Bridge | 0.53 | 0.1407 |
| Mt. Auburn / Watertown Bridge | Harvard Bridge | 14.07 | 14.1920 |
| Eliot Bridge | River St Bridge | 3.24 | 3.0920 |
| BU / Cottage Farm Bridge | Longfellow Bridge | 4.78 | 4.1205 |
Rounding the distances of the loops in the original history to the nearest mile and reading alphanumerically gives the answer MECHANICAL IMPEDANCE.
In the alterniate history, reading the decimal parts of the distance of each loop (the part that would be rounded off when rounding to the nearest mile) alphanumerically in pairs spells DAY FOURTEEN PLAQUE WILLIAM A BILLINGS TITLE. Going to the plaque on the south end of the Harvard Bridge reveals that William A. Billings was the DEPUTY CHIEF ENGINEER.