Do exactly what the chart sez.. and will find youre own answer: In this example, we assume that your vacuum source pulls 20 mmHg (20 torr), and that you want to determine the boiling point of water at that vacuum. The boiling point of water at normal pressure is 100°C. With the aid of a ruler, draw a line from 20 mmHg in the pressure graph (to the right), through 100°C in the middle graph ("boiling point corrected to 760 torr", this is the normal atmospherical pressure), and where this line intersects the line to the left ("Observed boiling point"), take your reading. About 15°C, right? This means that at a vacuum of 20 mmHg, water will boil already at 15°C, below normal room temperature. Compliments of Rhodium:-
https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/nomograph.html
For example if you want to distill your oil under reduced pressure. Safrole has a Bp of ~235 rnd abouts" correct me if wrong, but you can not heat the oil to that temp otherwise it will decompose (which you prob are aware of)so therefore, it is done under reduced pressure. So this is how its done: Work out what pressure you can reduce to, lets say 20mmHg Torr which is the column on the right, then you draw a line from 20mmHg Torr to the middle which is ~235'C (so you have a line gong from right to left thus far, which ends up on the left side which is ~120. So all you do is work on the same principle for other reduced pressure distillations. Water. say we will reduce the pressure to 60mmHg and we know the Bp is 100'C, so we draw a line from 60mmHg on the right through the middle to 100'C and arrive at the destination on the left which is ~ 30'C. So that answer your question about Rhodium and Vogel, Rhodium is correct and Vogel made a type error, shame on Vogel"
If this does not help, you are in the wrong field of interest, i dont no what else to say, but that hope this helps a bee or two.
Also as rhodium also states that this is an ~approx but however a good one, give or take a little. But atleast you have a ruff idea as to when it will come over.."