Mr. De la Rue's scientific and very useful diaries, memorandum-
books, and pocket-books for 1870, edited by Mr. Glaisher, have already appeared. The strong russia-leather pocket-book for gentlemen, the. gilt green morocco pocket-book for ladies, and the large red-letter diary and improved memorandum-book for ordinary household use, are, we think, the most instructive and convenient, as well as prettiest, things of the kind which appear. We would suggest to the editor that he should put a little more explanation into the (smaller) ladies"' memorandum-book, where the table of expansions of given substances. is given without any explanation of what the temperatures are,within which the expansions are supposed to take place, or what the supposi- tion is as to the volumes from which the expansions are supposed to start. These explanations are given clearly enough in the larger diaries, but in the smaller, the ladies' diary, the table of expansions ap- pears in a most enigmatic form, and one certainly not in the least cal- culated to make science intelligible and attractive to women. If it were necessary to abbreviate so far as to leave out the explanation, it would have been better to have left out the table altogether. The astronomical diagram this year is a picture of the total eclipse of August 18, 1868, with those various red protuberances visible which have since been shown to be flames of burning hydrogen gas. The highest of these enormous tongues of flame seems to have reached the height of
90,000 miles and upwards above the sun's surface, nearly four times the length of the earth's equator ! The scientific information furnished in the diaries is very judiciously chosen, and the get-up of the pocket- books is as good as possible.
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