Answer:
Holmes did not leave immediately for Dartmoor when he received the telegram from Colonel Ross because he couldn't believe immediately that the most remarkable horse in England could be missing without someone knowing. Therefore, he was expecting to hear that the horse has been found before taking any action.
Explanation:
When Holmes got no information about the horse being found, he decided to take action.
"Silver Blaze" is a short story written by Conan Doyle. The story talks about the disappearance of the great race horse, Silver Blaze and the murder of the trainer, John Straker.
Colonel Ross, the owner of the horse invited Holmes to help investigate the case. Holmes took his partner, Watson to Dartmoor in order to investigate the case.
