The short answer is Maybe.
The first adaptor (sic) is rated @ 1000mA output (1A), while the second is rated @ 750mA (0.75A). If the device requires LESS than 750mA, then the answer is "Yes" it will work fine. If the device requires more than 750mA then the answer is "No" OR "Only in a pinch". Many devices come with adapters rated higher than the device requires, additionally many devices only use the full load rating in rare circumstances; however, many devices also come with an adapter that barely meets the device's requirements......
"Safe". That was the question. Most likely it is "Safe" from the stand point of not burning the house down as long as the new adapter is "UL Listed". This implies that the adapter has an over-current protection circuit which will prevent it from bursting into flames or otherwise self-destructing....that being said, if the adapter is connected to a life support system and it shuts off every two minutes well that may be problematic.
It would be best to get a properly rated adapter (1000mA or greater). They are dirt cheap and pretty easily found, but if you are in a pinch, and the device is not part of a critical system, then the 750mA adapter may suffice for some interval w/o catastrophic failure.
Fish
