Page:Science vol. 5.djvu/305

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��in vegetable paleontology will perhaps iegar(i >ae still more im|K)i'tanl the discovery and care- ful characterizatioD of the twenty-eight forms which the author deaciibes as wliolly new to science, twenty-six of which receive the rank of species, and for the satisfactory elasBifica- tion of which he has found himself obliged to create the two new extinct genera, Merteii- sides and PaeudodanacopBis. Of these twentj'- six new species, eight are allied more or less closely to known forms, leaving eighteen spe- cies so distinct that the author has been un- able to compare them with any thing Uiat has been hitherto described. This is remarkable, in view of the great uniformity which is gen- erally found to exist in the floras of the enrlicr geological formations at points the most widely separated geogiaphically. It seems to indi- cate an unexpected divergence of the mcso- zoic flora of North Amerieii fW»ni that of Europe and other districts of the eastern hemisphere.

An important feature of the work, not indi- cated iiy its title, is a careful revision by Pro- fessor Fontaine of the researches in the same line of Dr. Ebenezer Emmons in Noith Caro- lina, made some thirty years ago, and pub- lished in part vi, of his "American geology,' 1857. The fossil plants found by Dr. Kra- mons. and figured in this work, arc described under the head of ' Fossils of Ihe triaa ; ' but Professor Fontaine thinks he has conclusively shown, from a study of his figures and descrip- tions (the fossils themselves having been de- stroyed during the war), that this 'triaa' of Emmons in North Carolina is identical with his ' older mesozoic ' of Virginia.

The work is copiouslj' illustrated, there be- ing, in all, fifty-fbur plates, the last six or seven of which are devoted to the reproduction ol' the figures of >!^mon8. The photo-engraving process is employed, and we haie here a stand- ard from which to judge of its applicability to the illustration of fossil plants. Jn some re- spects it proves quite satisfactory ; at least, when we consider its cheapness, and the ad- vantage it thus furnishes of allowing, at mod- erate cost, Ihe ample illustration of species, which is 80 great a necessity in this branch of paleontology. But we do not think the most has been made of the process iii llie present work.

The index, which is otherwise good, con- tains one feature which cannot be too highly commended to authors of such works. This is the i-cference to plate and figure, iis well as to page : which, in more than half the cases, the reader the lahor of looking twice.

��Di'KiNti the period covered by the observa- tions contained in tlicse two volumes, the naval oliservatory was under the sui>erintend- ency of the late Rear-Admiral Rodgers. His geueral reports to the chief of the Bureau of navigation, on the work of the institution, were promptly issued in the latter part of the years to which Ihey refer, and are reprinted, as customarily, in the annual volumes.

Pursuant to its policy, inaugurated some five years ago, of i-edncing the size of its bulky publications, — a policy which has met with universal commendation. — the obsenalory might now go farther, and expunge a good fraction of the protracted and annually reit- erated introduction to the observations with the transit- circle. We seriously question whether disastrous ambiguity would ensue if we were not told, with every year, that the ridge of the roof covering the transit-circle extends east and west; and that the hole in the cube of the axis of the instnimenl is 2.ri inches in diameter; — to say nothing of the continued reprint of formulae and details of reduction, which everj- astronomer, who has occasion to consult the volume, keeps con- stantly in mind. This introduction now occu- pies about one-fourth of the entire volume, includiug observations with all the instruments of the establishment, and the several appen- dixes. We suspect, however, tiiat the only suQlcient remedy lies, not in excei-ption, but in rewriting 06 initio, oil the supposition that those who will read the introduction already know something.

The newly adopted form in which the obser- vations with the trans! t-circle are published seems to have been very carefully studied, and is in everj' way a model. We should like to he able to write as stron^y of the precision of the results of stellar and planetary observations with this instniment, the character of which is too well known to require characterization here. Presumably, no one is responsible for the fact that they are not better ; but certainly the fre- quent change of observers, unavoidable in so far as the observatory itself is concerned, is not conduci\c to results of a high order of accuracy.

During the yeiu's 1879 and 1880. the transit- circle was under the charge of Professor Eastman, and was employed with customary

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