difficulty in the full performance of the duty here so lucidly and tersely set forth—that, namely, of comparing our own with other observations. It occurs to a great extent in the department to which the present speaker’s chief attention has been devoted, that, namely, of physics. Much valuable work and information is stored away in papers read before learned societies, in small detached pamphlets, in foreign and scientific periodicals, and similar places very hard to reach for purposes of consultation. Hence follows no little repetition of labour in rediscovery, and the consequent disappointment of perfectly conscientious observers who have unwittingly gone over the same ground as their forerunners in science. It is, moreover, from comparison of one’s own views with those of previous labourers, if it be performed in a conscientious and thorough manner, that new views and ideas often arise.
It is not, however, so much in the seeking out of new facts in Nature that these canones help us, as in the suggestions for the communication of knowledge, a function especially important in the
