When Arte enters the embassy kitchen the outside window panel on the door are frosted. Later when he open the door to let Jim West in they are clear.
When Arty first tries to remove the box from the piston safe there is a short chain that keeps him from moving the box past the out rim of the safe. He is thus forced to do his work within the safe. When he finishes and whistles to Jim to turn on the large piston the chain is more than twice as long as before.
President Grant is shown arriving that the foreign embassy with no Secret Service protection whatsoever.
The cat wakes up at the same time as the guards; however, having received the same dosage of the knockout gas as the men but with a far smaller body mass, it should have been asleep for a much longer time if, indeed, it did not turn out to be a fatal dose. Update: If we assume the gas was absorbed through the lungs, the cat's lungs being relatively smaller than human lungs (with less surface area inside them to absorb oxygen and other inhaled gases), then the actual amount of gas the cat inhaled and absorbed would have been correspondingly less than the humans.
Jim is supposed to be showing the daughter of the Lithuanian Ambassador the Big Dipper. BUT Lithuania in the 19th Century was part of the Russian Empire. Further, not only was it not independent and therefore not worthy of a diplomatic corp, but it was experiencing a Tzarist policy of Russification after rebellions in 1831 and 1863. So, Russia was NOT about to let Lithuania have an embassy ANYWHERE.
When West looks at the picture with a magnifying glass, he holds it within a couple of inches of the picture, and holds the picture and glass at arm's length. This would give almost no magnification. One wants to hold the glass about halfway between the eye and picture for maximum magnification.
Jim was supposed to have been with the daughter of the Armenia Ambassador. BUT Armenia in the 19th Century was divided between two different empires, Russia and Ottoman, and neither empire was about to let Armenia have an embassy ANYWHERE.
When West is catapulted up through the "abandoned" well shaft he is seen looking downward as he approaches the Gazebo roof structural support beams. Anyone hurling upward would be looking up to avoid crashing into the roof structure and see when to grab on to the beams. Obviously this was filmed with Robert Conrad hanging from the beam and letting go so that when played backwards provides the illusion of moving upward. To do this properly he really should have been looking up when letting go of the beam and remain that way as he fell past the camera view, completely trusting the crash pad below would cushion his fall.
During the fight in the security room, in several cases someone falls against the red pipe leading to the open/close valve, which presumably would indicate a hot pipe - yet there is no indication that the person is being burned. Also, during the fight, one of the workers falls back against the gray-green pipe in the valve assembly and the whole assembly visibly wobbles. If the assembly were built to contain the high pressure steam, there is no way it should have wobbled when the man fell against it.
The film projector is referred to several times as a kind of advanced "kinetoscope," but the kinetoscope wouldn't even be conceived until at least 1888, while this episode takes place during the presidency of Ulysses S. Grant (1869-1877). The kinetoscope was not capable of projection for multiple viewers, but required an individual to look through a window to see the film.
The recording of West's and Gordon's voices being used to deceive the Baron's men is playing on a disc. The phonographic disc was not developed until the late 1880s and did not become a standard until some fifteen years later.
This is actually an anachronism of behavior. At the beginning of the program, Jim is noticed by the bad guys to be missing. A search is begun for Jim and he is soon discovered in a side room embracing the daughter of the Armenian Ambassador. But the setting is the Victorian era and public displays of affection were contrary to the social norms of the times and would have resulted in scandal and humiliation for the family (hardly the objective for any public servant). Rather, this is more in line with the social norms of the time of the filming, the 1960s.
Several things surrounding the information about the architect (Quincy) and the stonemason (Dick January) don't make sense. If the subterranean alterations to the Embassy were completed on May 6, 1871 (as noted on the photograph), and Dick January was worked over until he was almost dead, the events in this situation must have taken place many months after that date, as Dick January was quite healthy at the time West interviewed him. Also, there is no indication of when Quincy died/was murdered, so the implication is that this is relatively old information - yet Quincy's office still bears his name and title, and many of his drawings are still there, and there was no dust in the room. Also, there is no way the Embassy would ever have allowed the plans for the alterations to be kept at Quincy's office - they would have specified that all work be done at the Embassy itself. So, finding the empty tube that supposedly held the Embassy plans made no sense, nor would the presence/existence of the photograph in Quincy's office - the Embassy would never have allowed the photograph to be taken.
When West is in the Embassy security room holding the valve in the open position, he would have been ingenious enough to pull his belt off and use it to hold the valve in the open position so he could protect it.
When Artie is opening the black box in the safe, the wax seal comes off in one piece. Rather than recreating the seal as he did, he would have simply melted some wax onto the box and re-stuck the seal to the box.