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and a shilling per volume more for binding decently in cloth. Such being the case, the anti-climax to which I have alluded is simply inconceivable. On application being made for copies to be sent to our public libraries, the Government has declared that it cannot afford these few ninepences per pound and shillings per copy.

Compare this with the proceedings of the Government Printing, Office at Washington, whence are issued the noble records of "The United States Naval Observatory," &c. These are not only distributed freely to the American public libraries, but are sent across to the scientific libraries of Great Britain, and not only to them but to individual members of the scientific societies. I have a very valuable series of these reports, and of the Reports of the "Department of the Interior," and other works issued by the United States Government from their Printing Office at Washington. These are sent over to me through their agent, and carriage-paid to London, upon no other asking than that of replying to an official letter enclosing a list of works from which I am asked to select those I desire to have. Generally speaking they are invaluable as original records of most important and laborious scientific investigation. All Englishmen desiring to be patriotic must be bitterly ashamed of this melancholy contrast.

The present favourable position of the most wonderful and beautiful of all the heavenly bodies, the planet Saturn, with its mysterious ringed appendages, reawakens an old project that I have often longed to carry out, viz., the establishment in a suitable part of London of a popular observatory. I don't mean an establishment with amateur observers pretending to do original astronomical work, and thereby supplementing or superseding the Greenwich business; but simply a good astronomical peep-show, where millions of people who have never looked through a powerful telescope, and otherwise never would do so, might have an opportunity of seeing for themselves some of the magnified glories of the heavens. I believe that it might be made commercially self-supporting if well done, and all pedantry severely excluded. No mathematical work could be done nor need be attempted. Both reflecting and refracting telescopes equatorially mounted with the simplest of efficient clockwork would be required; and one telescope should be provided with spectroscopic appliances. The physical phenomena are all that the popular visitor would desire to see, and the fact of having once seen the most striking of these would leave a life-long impression on all intelligent men, women, and children. A small charge, with proper regulations as to time allowed at each instrument, would cover all expenses, including a modest salary to the showman-I beg his pardon--the director. The sun and moon should be shown first with a low power to display all the disc, then with a high power for particular details.

Apropos to telescopes, Mr. Cowper Ranyard lately read to the Astronomical Society a note on the blurred patches that appear in the splendid photographs of the sun taken by M. Janssen at Meudon. Janssen is himself inclined to attribute them to solar clouds or gaseous matter above the photosphere, but Mr. Ranyard has made some experiments indicating that they have their origin within the telescope itself, and are due to heated currents of air in the tube. He produced exaggerated representations of these in the form of ripples by placing a heated body inside his telescope. The difficulty of maintaining a perfect calm within the tube of a large telescope must be great, and the sensitive film used for these instantaneous photographs cannot fail to display any disturbance affecting either the transparency or refractive power of the air in the telescope. I think the question as between these two explanations might easily be settled by taking several pictures of the sun at short intervals apart. If the light patches or blurs are due to cloud-matter in the sun they should appear at the same place in all the pictures, seeing that the space represented by every square millimetre of such pictures is so enormous that no cloud could travel to a sensible distance on the picture in any short period of time; while, on the other hand, the atmospheric irregularities within the telescope must be visibly shifted during small fractions of a second.

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leak, or are very difficult to clean. The underdescribed form, which I have lately contrived and used, obviates these defects, and may therefore be of interest to the readers of `SCIENCE-GOSSIP. It is of very simple construction, and can be made up at a trifling cost by the help of any ordinary metal worker.

Take a stout ground-edged glass slip, and have fitted to it two sheaths of thin brass, about 3-inch wide. These should be made to fit closely, but not so tightly as to prevent the glass slip from sliding easily through them. To the middle of one end of each sheath is soldered a small brass arm (shaped as in Fig. 2), carrying a fine screw on one arm, which, when secured in position, projects about 4-inch beyond the end of the sheath.

A piece about 1 inch long, cut off a thin glass slide, and a thick india-rubber ring (those used for Cod's patent soda-water bottles serve excellently) completes our requirements.

To put the parts together, slip the sheaths, one on to each end of the glass slide, with their two little screw arms projecting towards each other. Now cut

a small piece out of the circumference of the indiarubber ring, and place it on the slide between the sheaths, with the opening towards one of the long sides of the slide. Place on top of the ring the short piece of glass, and slide the sheaths towards each other, till the small screws project over its ends. Then, by turning down the screws, the ring is compressed between the two pieces of glass, and a perfectly water-tight cell results. By using rings of different thickness, cells of every convenient depth may be obtained.

When one has finished working with it, the whole

It consists of a block of well-seasoned wood, 5×3×3 inches. At 1 inch from one end of the block a hole is bored of such diameter as may be necessary to admit the cylinder of a pewter syringe of about inch internal diameter. This hole runs vertically from the upper to the lower surface of the block. Across the opposite end of the block is cut a horizontal notch, 1 inch deep and wide. Cut off the nozzle end of the syringe, so as to leave a piece of tube three inches long, and cut the handle off the plunger so as to leave only the piston part. This should be packed as neatly as possible, and have

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thing can be taken to pieces in an instant and cleaned. If a well-polished piece of glass, free from flaws, be chosen for the upper plate, its thickness will not be found to interfere very materially with the performance of any power below -inch.

While on the subject of cheap apparatus, I will describe a form of microtome which can be made by any one, with a slight mechanical turn, for about eighteen-pence. In many essential points it is almost identical with that of Mr. A. B. Chapman, described in your June number, as, however, I constructed and used it more than ten years ago, I must claim to be guiltless of plagiarism.

Fig. 5.-Upper Surface of Microtome. soldered to its upper surface

a small Z-shaped piece of tin, so as to give the parapin a firm hold on the piston.

Cement the tube into the hole in the block with shellac or elastic glue, so that

one end projects about the thickness of a glass slide above the upper surface, and cement on to the upper surface of the block, along each side of the projecting portion of the syringe, an ordinary ground-edged glass slide, taking care to choose a pair of equal thickness, and with well-rounded edges. Now procure a fine screw running on an oblong-nut: the nut to have a hole to take the head of a wood-screw at each end, and secure it by means of a couple of screws to the under surface of the block, so that the fine screw works up and down in the centre of the pewter tube. Get also one of the coarse iron screws with brass fittings, such as are used to fasten oldfashioned window sashes, procurable from any ironmonger, and fasten this to the under surface of block, so that the coarse screw may work into the notch already described.

To use the machine, place it with the edge of a lath projecting into the horizontal notch. Then by screwing up the coarse screw, it will be firmly clamped to the table, and projecting beyond it, a position extremity convenient for working.

Now turn down the fine screw, and push the piston, with the finger, down through the tube on to it. The well is then filled with a melted mixture of five parts solid paraffin to one part tallow, and the object to be cut embedded in this. The sections are then taken in the usual way, the two

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ground edged slides acting as the guides to the

razor.

With one constructed in this way, I have procured sections finer than I have got with any other nonfreezing machine.

I have one further limit to add. In cementing on the two glass slides, take care that, if not quite horizontal, they may tend to form a V, rather than an A with each other, as should the inner edges be the least higher than the outer, the razor will be very quickly blunted, whereas, on account of the razor edge being, as a rule, somewhat curved, the circumstance of the outer edges being a little high is of no moment. Also do not be tempted to make your well of large diameter; inch is quite as large a section as one is likely to want, and the smaller the diameter of the well, the more even will the sections be. Of course a brass tube and plunger may be made

form sori, seated on scarcely perceptible spots, on the underside of the leaves (only rarely on the upper side); the sori were scattered, or irregularly grouped, occasionally in orbicular clusters, round or oval, averaging 300 μ in diameter, convex and elevated. The epidermis persisted round the sori, forming a somewhat dome-shaped investment, ruptured at the summit, where it was pale in colour, but below darkbrown, owing to the paraphyses showing through. These paraphyses, which formed the most striking feature, were arranged in a single ring, surrounding the sorus, just within the persistent epidermis; they were dark-brown, shining, oblong-cylindrical, enlarged at the apex (club-shaped), inclining inwards towards the centre, from 80-100 μ long or more, and about 12-15 μ thick. (Figs. 6 & 7.)

Within these were the uredo-spores, oval, obovate, oblong, or roundish in shape, surrounded by a very

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thick, colourless, warted membrane (Fig. 8, a); contents very pale yellow, with a few oily drops; 30-50 μ long, and 20-24 μ broad. No other spores than these could be seen in situ; but, on scraping off a few sori, a small number of meso-spores were observed, which differed in being of a darker brownish colour, and less or not at all warted surface; the transition from the uredo-spores to the meso-spores could be clearly traced. (Fig. 8, b and c.) A persistent search revealed a few teleuto-spores, which were oval, not constricted, smooth, and dark-brown; but so small was the number that I incline to the opinion that these were accidental intruders, and did not belong to the same species. They might have been blown on to the leaf from some neighbouring plant infested with a Puccinia. (Fig. 8, d.)

The plants on which this fungus was found were two small seedlings, not in flower, growing on rubbish which had been thrown out of the canal in cleaning it;

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