116 Transactions of the lloyal Microscoineal Society. 



borders springing from the points of elongated needles. Most 

 of the patterns run into each other, and they all show Maltese 

 crosses of colour with the polariscope. The artist has shown small 

 rosette patterns from this slide. Some rosettes as small as 1 — 400", 

 others 1—100". 



Fig. 5. Potassic chlorate and silica. Some of the various 

 patterns obtained with this salt. The architectural, pedestal-look- 

 ing group exhibits curves as well as angles. Many flat crystals 

 show sihca cracks, which look as if engraved or incised : they do 

 not go through the substaace. Pedestal group about 1 — 40". 



Fig. 6. Cupric sulphate and silica. This contains figures 

 selected from a variety of patterns. The sketch exhibits a curved 

 floral pattern of considerable complexity and of great beauty with 

 the polariscope, and also small rosettes. The latter, with high- 

 powers, is seen full of minute workings, approximately like diatom 

 headings. Eosettes from 1 — 50" to 1 — 20". 



Fig. 7. Cupric sulphate and silica. A nautiloid pattern, com- 

 posed of curved lines, the chief arrangement of which is from right 

 to left, as seen in an inverting instrument, with parts running the 

 opposite way. The imbricated scale or feather-like aspect results from 

 silica cracks .and modifications of level and thickness. In this slide 

 also is shown what in former notes was designated the " pavement 

 pattern." Nautiloid j^attern rather less than 1 — 40" long diameter. 



Fig. 8. Cupric sulphate and silica. Complicated spirals, with 

 minute bead-like divisions. Many of the spirals in this slide run 

 into each other and are confused. The circles containing the spirals 

 up to about 1 — 34". 



Fig. 9. Salicine and sihca. Small flower patterns. Many of 

 them, with ^th and A or B eye-piece, exhibit radial lines of minute 

 beads and granules, arranged to produce effects most like actino- 

 cyclus. Small ones 1 — 400". 



Fig. 10. Cadmic chloride and silica. See remark at the end of 

 description of Fig. 1. Size from rather more than 1 — 100" to 

 very minute. 



Fig. 11. Tartaric acid and silica. ' This combination gives a mix- 

 ture of irregular pavement pattern, with more or less floral patterns. 



Fig. 12. Sahcine and silica. In this slide the tangential forces 

 have developed the radial patterns seen in common slides, with 

 flowering curves hke fine foliage. The variations in thickness, &c., 

 give rise to a greater range of tint and more colour harmony than 

 in ordinary slides. Floral pattern about 1 — 8". 



Fig. 18. The patterns in this slide are extremely complicated 

 and elegant. Very delicate fan-shaped radial groups give the 

 appearance of a delicate tissue. They spring from needles, and 

 are exquisitely fringed. Some complete circles about 1 — 50". 



