A. hale means healthy and strong :)
He is using a like/as example with "my own line of reasoning is to myself as straight and clear as a ray of light" and if he is using the suns light as a metaphorical thing and the light represents purity or intelligence then he is saying he is very logical and knows what is going on. He knows what he stands for and as he stated "will pursue his principles unto death" he is willing to die for what he believes in....i hope this helped
