HARDWICKE'S SCIENCE-GOSSIP. 



105 



ON CLEANING DIATOMACEOUS 

 GATHERINGS. 



VARIOUS methods of preparing Diatomaceous 

 material for mounting have from time to time 

 been given in the numerous text-books treating on 

 microscopic manipulation. I will, therefore, sup- 

 pose the reader to be well acquainted with the use 

 of nitric acid for the purpose of getting quit of 

 delicate vegetable and calcareous matter, and also 

 with the sulphuric acid and potash process. The 

 manipulator is, however, often disappointed with 

 the appearance of his slides after using the methods 

 just alluded to; one source of annoyance is the 

 precipitation of the diatoms in little flocculent tufts, 

 and although shaking the test-tube or bottle tem- 

 porarily breaks them up, they form again when a 

 drop is placed on the slide: the cause of this appears 

 to be the remains of minute fibrous matter; this 

 may be got rid of by adopting the following plan. 

 Pour off the supernatant water, and replace with 

 strong ammonia, cork the test-tube or bottle, and 

 allow it to stand for two or three hours, then 

 shake it well, and the diatoms will be found to fall 

 gradually ; and, after the lapse of an hour, if the 

 diatoms are minute, pour off the ammonia, and 

 wash the deposit with distilled water, until all 

 traces of it are got rid of. Ammonia, unlike the 

 caustic alkalis, do not injure the siliceous valves, 

 even after the lapse of weeks. 



Another, and perhaps a still greater cause, of 

 what are usually known as dirty slides, is the pre- 

 sence of minute particles of sand, which no amount 

 of washing or dividing into densities will eliminate. 

 The plan I am about to describe will be found 

 effectual in getting quit of this annoyance. The 

 modus operandi is as follows : — I take two slides, 

 which we will call A and B ; on A I place a drop 

 (not too small) of the material, on B a drop of dis- 

 tilled water ; I now take up A, and shake it so as 

 to cause a slight whirling motion in the drop, and 

 then suddenly tilt it towards one corner, the water, 

 of course, flowing to the lowest point, the drop I 

 allow^to run into the drop on slide B ; it will then 

 be found that the water has separated the diatoms, 

 leaving the sand behind. 



If the quantity of material is small in quantity 

 and rare, the sand and the few diatoms mixed with 

 it can be washed into a small test-tube, and the 

 eliminating process just described may again be ap- 

 plied to it. If the material contains large and heavy 

 forms, such as (Eupodiscus and Aulacodiscus, they 

 are better picked out, as from their size they are 

 apt to be left behind. I have, however, found no 

 difficulty in separating the largest forms in the 

 Toome Bridge deposit from the sand by this 

 method. If the material is very sandy, the drop 

 on slide B may be treated as it had previously been 



on slide A. This method, although occupying some 

 little time, and requiring a little practice, will 

 amply repay the manipulator in the greatly im- 

 proved appearance of his slides. 

 Norwich. P. Kitton. 



SONG LARKS. 



"VTATURE is again resuming her lovely robes : 

 ■L^ we shall soon be surrounded by our beauti- 

 ful choristers that charm us as we stroll through the 

 wood. The charming wood, clothed as it were by 

 magic, the flowering thorn, the pretty primrose and 

 other little flowerets, all seem smiling at their old 

 friend the ivy-clothed oak. How new, how enjoy- 

 able ; yet spring is but a repetition ; how still, how 

 grand everything is as we stand, listening to the 

 sweet note of some bird that sings so freshly in 

 Nature's great concert-hall. Migratory birds are 

 fast arriving to swell the sublime chorus. 



"We shall now enjoy the grotesque flight of the 

 Titlark, toying and treating us to jerks of his finely 

 measured note, singing with amorous vigour to 

 charm his mate, whom he has preceded by a few 

 days. The Titlark is a delicate, pretty little bird, 

 slight and fragile in appearance ; it is about half 

 the size of the Skylark ; it builds in the grass, and 

 sometimes in low bushes; it runs very swiftly; it 

 sings on the ground, on the branch of a tree, and 

 on the wing, but does not mount like the Skylark. 

 The song of the Titlark is good and very pleasing, 

 and is much used to teach other birds, but mostly 

 to teach the Linnet and Canary. When first caged, 

 there is a little trouble in getting them to feed; but 

 when you get over that, they soon sing. To get 

 them to feed, you should place a few mealworms 

 under a glass, around which you can give them 

 some bread and egg chopped fine, on the top of 

 which you can strew a few mealworms cut in pieces. 

 When they see the worms move under the glass, 

 they will pick at them, and thereby will be tempted 

 to eat those around the glass : after a day or two 

 they will take their food readily. 



But for all this they do not live long in captivity, 

 seldom living more than one season. They lose 

 their appetite ; they also moult twice in a year, 

 which mostly reduces them to extreme weakness, 

 from which they mostly die. 



There is another bird much like the Titlark, 

 called the Pipit. It is sometimes mistaken for the 

 Titlark by inexperienced lark-fanciers; but the 

 Pipit is more diminutive and not so bright in colour : 

 they are sometimes taken in great numbers in the 

 autumn : it is soft-billed, feeding mostly upon flies 

 and larva;. As a caged bird it is perfectly useless ; 

 it has not any song, merely a call— pip-pit. 



But the Lark is raised to the highest pitch o f 

 beauty in the Woodlark, whose song is perhaps 



