It is true that during their explorations they often faced difficulties and dangers of the most perilous nature, equipped in a manner which would make a modern climber shudder at the thought, but they did not go out of their way to court such excitement.
perilous 是形容词，意思是”危险的“， nature是名词，意思 “性质”，the most perilous nature d的意思是最危险的性质，dangers of the most perilous nature 按字面翻译是“具有最危险性质的危险”，也就是指从性质上来说最为危险的危险。你看多罗嗦，实际上作者要说的也就是最大的危险，用日常英语说就是the biggest danger。不过原表达方法从问题上来说很正式、端庄，语气也较强。
