I am, in consequence of this situation, now forced to look for other acquisitions, which lead me again into investigations, accomplishments before known only be observation; but now I must begin to prepare the way for the practical skill. I even now in this short space of time find many things to be acquired, before unthought of. All must be had, arranged before a third step can be accomplished. Thus you will observe that, one thing alone will not do, but when you get one, a corresponding becomes necessary. And in many cases absolutely indispensable. Think of the principle involved in these remarks and mind them. They will be of infinite advantage to you.