Feb. 20, 1890] 



NATURE 



379 



No doubt the sea-side of our south-western coasts— I mean 

 its creeks, not "the thundering shores of Bude and Bos" — is a 

 paradise for microscopists ; but there is no need that we should 

 travel so far afield. Our inland woods, our lanes and pasture-;, 

 will yield to us a thousand beauties and wonders. The scarlet 

 pimpernel will show its glorious stamens, the flowers of the 

 wound-wort glow like a costly exotic ; wild mignonette will rival 

 in its fantastic shape the strangest orchid ; the humblest grass 

 will lift a tuft of glistening crystals ; the birch and salad-burnet 

 shake out their crimson tassels ; the Jungermanns will display 

 their mimic volcanoes, the mosses unfold the delicate lacework 

 of their dainty urns. But the time would fail me to name one 

 tithe of those sources of wonder and delight that lie all around 

 us ; and most of which, as in the case of the Rotifera, contain 

 numberless points on which we are all happily ignorant, and 

 therefore in the best of all possible conditions for deriving end- 

 less pleasure and instruction from them. Besides, my time and your 

 patience must, I think, be drawing to a close ; I would then only 

 once more suggest, that we should not only explore for ourselves 

 all these " pastures new" — no matter how imperfectly — but that 

 we should encourage those, who can be our most efficient guides, 

 to indulge us with the main results in the simplest language. 

 Surely one of the most charming subjects, that can interest 

 human beings, admits of being so treated ; and there can be no 

 good reason why the Muse of Natural History (for no doubt there 

 is such a Muse) should resemble that curious nymph among the 

 Oribatidce, whom Mr. Michell found lying under the moss of 

 an old tree, half smothered in a heap of her cast-off" skins, 

 admirable types ;of successive classifications, and abandoned 

 nomenclature. 



Happily, however, books in such matters are of little import- 

 ance ; and names and classifications of still less : both these 

 latter, indeed, are of ephemeral interest ; they are the pride of 

 to-day, and the reproach of to-morrow. It is to the living 

 animals themselves that we must turn, fascinated not only with 

 their beauty and their actions, but with the questions which the 

 contemplation of them perpetually provokes, and very rarely 

 answers. 



For, in the long procession of the humbler creatures, who can 

 tell where life first develops into consciousness, and why it does 

 so ; where consciousness first stretches beyond the present so as 

 to include the past, and why that happens ; or at what point, 

 and why, memory and consciousness themselves are lighted up by 

 the first faint flashes of reason ? 



We know nothing now of such matters, and probably we never 

 shall know much ; but the mere fact that the study of natural 

 history irresistibly draws us to the consideration of these ques- 

 tions, gives to her pleasant features an undoubted dignity, and 

 raises the charming companion of our leisure hours to the rank 

 of an intimate sharer of some of our gravest thoughts. 



THE TOTAL ECLIPSE. 



T^HE U.S. S. Pensacola arrived at Saint Paul de Loanda on 

 December 6, after a voyage of 51 days from New York, 

 having made the ports of Horta, Fayal, in the Azores, Nov- 

 ember 2-3 ; of Saint Vincent, in the Cape Verdes, November 

 10-12; of Saint George's Parish, Sierra Leone, November 18- 

 20 ; and of Fllmina, on the Gold Coast, November 26-28. 



Immediately on landing at Loanda, it was found that the Rio 

 Quanza steamer, sailing bi-weekly for Muxima, had left two 

 days previously, and that recent washouts along the line of the 

 Caminho de Ferro Trans-Africano made it impracticable for 

 the Expedition to reach either Muxima or Cunga early enough 

 to allow sufficient time for moun'.ing and adjusting the instru- 

 ments for the eclipse. 



I therefore at once decided to locate the Expedition at or 

 near Cape Ledo. Mention should be made here of the courteous 

 civilities of His Excellency the Governor of Loanda, for his 

 kindly interest in the Expedition, and the facilities he offered 

 for the prosecution of the various fields of its work. 



The Pensacola came to anchor alongside H. M. S. Bramble in 

 the little bay to the north of Cape Ledo, on the afternoon of 

 Sunday, December 8. The Eclipse Station was selected in a 

 very favourable spot close to the shore cliffs, and the sites of the 

 principal instruments were determined before night. 



A week or ten days' hard work sufficed for getting a large 

 amount of the apparatus in readiness for the eclipse. I placed 

 Prof. Bigelow in charge of the direct photoheliograph of nearly 



40 feet focal length, and detailed Mr. Davis to assist him. 

 Mr. Jacoby was intrusted with the charge of the time-determina- 

 tions, and longitude and latitude work. The Bramble was at 

 Cape Ledo on a mission like that of the Pensacola, and attend- 

 ing upon the English Eclipse Expedition in charge of Mr. A. 

 Taylor, F.R.A. S. ; and through the courtesy of her commanding 

 officer. Captain Langdon, R.N., advantage was taken of her 

 run to St. Paul de Loanda and return, December 14-17, to 

 make a chronometric determination of the longitude, by com- 

 parison with the time at Loanda as determined by Mr. Preston, 

 who was left there by the Expedition for the gravity and mag- 

 netic work. Also, on the Bramble's second return to Loanda, 

 on December 23, another comparison was made. 



Prof. Abbe was in charge of the meteorological work and of 

 the organization of parties of observers from the ship's company. 

 A large amount of valuable material results from his work. 



The mounting and adjustment of the extensive apparatus for 

 the total eclipse, I reserved for myself. A duplex polar axis 

 eleven feet in length had been constructed of six-inch iron 

 tubings, and mounted with great stability. This axis was 

 driven by powerful clock-work of extreme precision, made by 

 Mr. Saegmueller, of Washington. On this single axis was 

 mounted the totality-battery, consisting of 2 Brashear reflecting 

 telescopes of 8 inches diameter, four Clark telescopes of 3J, 5, 

 ^\, and 8 inches aperture, the second being rigged with an eye- 

 piece enlarging the sun's image to a diameter of 4^ inches, the 

 third being used as a high power directing telescope, while the 

 fourth, a photographic doublet with 10 inch back lens, loaned 

 by the Harvard College Observatory, was arranged for a series 

 of twelve exposures, two of which were made through an ortho- 

 chromatizing screen provided by Mr. Carbutt ; two six-inch 

 Dallmeyer rapid rectilinear lenses of 24 and 38 inches focus ; 

 one Schroeder triple objective, of 6 inches aperture and 22 

 inches focus ; one Gundlach orthoscope of 3 inches aperture and 

 21 inches focus ; two flint spectroscopes and one quartz spectro- 

 scope loaned by Harvard College Observatory ; a duplex photo- 

 meter of 75 inches focus also provided by Prof. Pickering, and 

 his reversing layer spectroscope for photographing a spectrum, 

 trail for fifteen seconds both before and after second and third 

 contacts ; a 5 inch Ross lens of 42 inch focus ; a 4 inch Spencer 

 objective of 36 inch focus, and a 6 '4 inch Merz-Clark objective, 

 both rigged with the means of automatic variation, of aperture 

 during totality ; and lastly, two duplex cameras provided by Dr. 

 Wright of the Sloane Laboratory of Yale University, for photo- 

 graphic record of the polarization of the corona. In all there 

 were 23 f>bjectives and two mirrors, with their axes adjusted; 

 into parallelism. 



With the exception of the Gundlach camera, which was re- 

 served for a special investigation of the extreme outer corona, 

 all this apparatus was operated automatically, by an adaptation 

 of the pneumatic organ- valve system of Mr. Merritt Gaily, of 

 New York. Exposing shutters were opened and closed, sensi- 

 tised plates were exchanged for others as soon as exposed, and 

 all the mechanical movements were accomplished with entire 

 precision. Also, by employing an ordinary chronograph in 

 conjunction with the valve system, the exact time of beginning 

 and end of each exposure became a matter of accurate record. 



All this apparatus was brought into operation during the 

 period of total eclipse, and over 300 exposures were made in a 

 period of 3m. losec. ; but no photographs of the corona were 

 secured, as the sun was completely obscured by clouds. How- 

 ever, the entire success of the pneumatic movements is a result 

 of no little value in view of eclipse work in the future. 



In addition to this, a silver-on-glass mirror, of 20 inch diameter 

 and 75 feet focal length, by Brashear, lent to the Expedition by 

 Prof. Langley, was so mounted as to throw an image of the 

 corona up the cliff" and just underneath the sun at the time of 

 totality. At the focus a beauiiful 10 inch image of the sun was 

 formed, and 20 x 24 inch plates of the highest sensitiveness 

 were in readiness to record the coronal streamers. This unusual 

 apparatus was also rendered inoperative by clouds. 



With the direct photoheliograph, however, very gratifying 

 success was secured. Seventy pictures of the partial phases 

 were made before totality, and forty after. The serious obstacles 

 to the operation of so long a tube were successfully overcome 

 by means of a skeleton mounting, a combined form of an equa- 

 torial stand and tripod; and Prof. Bigelow's sand-clock enabled 

 the precise and easy following of the sun. The revolving plate 

 holder, of 22 inches diameter, actuated automatically by com- 

 pressed air, in which the principles of the apparatus of the 



