unless we know why he toiled so hard: a railway signal-man sometimes works even longer without creating any public enthusiasm. The real interest of the incident lies in this: that Sir William Herschel had conceived the idea of a new form of telescope, and was labouring with almost frenzied energy to put it into execution, that the plan succeeded so well as to revolutionize all previous methods of making reflecting telescopes, and laid the foundations of modern stellar astronomy. This is the kernel; the memoir gives us but the shell. Again, throughout the book we have not a hint as to the boundary of Herschel's peculiar province in astronomy; in what condition he found the science; wherein he improved it; what object he proposed to himself; and how far that object was attained. It seems to us that the life of his faithful assistant, who shared all his labours and all his hopes, cannot be intelligently told without at the same time telling us this. We may be made to admire the energetic woman; but Miss Herschel would have felt anything but pleased if any one had admired in her the woman, at the expense of the astronomer.
The authoress sometimes does less than justice to the gifted lady who is the subject of her book. During her life, as her brother's assistant, he was, of course, commanding officer; his was the invention, the genius, the rapid intuition, and, most properly, the lion's share of fame. To her lot fell the duty of patient attention; hers was the labour of calculation; the arrangement and transcription of rough notes. Mathematical analysis belonged to him; arithmetical computations were handed over to her. But to carry out his instructions and to perform the tasks assigned to her required a large range of knowledge, as well as indomitable perseverance. It is therefore not fair to the memory of Miss Herschel to make it appear that she was profoundly ignorant of even rudimentary mathematics. To give an instance: an extract is given in the memoir, under the date 1786, from a MS. book belonging to Miss Herschel, and sent by her from Hanover to Sir John Herschel after his father's death. The authoress says, " The information is of a very miscellaneous kind, but matters connected with her special study form the greater part of the questions" which, as we are elsewhere told, Miss Herschel used to put to her brother when they met at breakfast before separating for their daily task. We are then favoured with three or four interrogatories, which the writer of the memoir may, perhaps, consider likely to elicit "information of a miscellaneous kind," but which Miss Herschel in 1786 would have looked upon as absolutely childish. E.g., "Given the true time of the transit, take a transit? . . . Of a logarithm given, to find the angle?"
Now, in 1786 Miss Herschel had been fourteen years her brother's assistant. On the very same page where this absurd extract is given, there is an entry in Miss Herschel's journal: —
4th. I calculated nebulæ all day, etc. . . .
9th. Calculated the places of one hundred nebulæ.
The lady who could make the two latter entries as records of her ordinary daily life would be little likely to ask for information as to the mode of taking a transit, or the way of finding an angle from its logarithm. It is obvious that the questions belong to the days when Miss Herschel first joined her brother at Bath, in 1772, when she was ignorant of almost everything except reading and writing. The memoir would be of little interest if it were not a record of difficulties overcome with immense rapidity by a very powerful mind. It is quite unfair to represent the Miss Herschel of 1786, who had already herself discovered a comet unassisted, and corresponded on equal terms with the leading astronomers of Europe, as asking childish questions of her brother. The questions are not worth noting at all; but if they are noted, they ought to be relegated to the first chapter as evidence of Miss Herschel's sincerity when she complained that she arrived in England absolutely ignorant of everything likely to be of use to her in the life that lay before her.
It is strange that we must go to a French philosopher for the record we
