315 



Young (H. D.). The Generation of Hydrocyanic Acid Gas in Fumiga- 

 tion by portable machines. — California University Agric. Coll., 

 Berkeley, Circ. 139 (N.D.), 8 pp., 5' figs. [Received 8th May 1916.] 



The tents used for fumigation with hydrocyanic acid suffer con- 

 siderable damage from burns by acid when the ordinary pot method 

 of generating the gas is employed, and therefore a portable generator 

 from which the gas may be delivered to the tent from the outside is a 

 distinct advantage, not only as preventing the damage to the tents, 

 but also as an economiser of material and giving better control. The 

 portable fumigating machine here described consists of a cylindrical 

 drum around the inner, upper part of which is a circular tank for cyanide 

 solution connected on one side with a pump, the dehvery tube of which 

 projects into the centre of the drum. By operating this pump the 

 cyanide solution may be delivered in measured quantities. The full 

 charge is 600 oz. pure sodium cyanide dissolved in 150 U.S. gals, water 

 placed in the upper tank and 600 oz. of concentrated sulphuric acid 

 diluted with an equal volume of water placed in the' bottom part of 

 the drum ; this is sufficient to generate the whole of the gas provided 

 for by the cyanide. The pump is graduated in ounces of soHd cyanide, 

 as this is the usual basis of calculation for the fumigation. The method 

 of mixture adopted, namely, of running a standard cyanide solution as 

 required into fairly concentrated sulphuric acid, involves the steady 

 dilution of the acid each time a charge is used. As this is contrary to 

 the usual practice, a series of careful experiments was conducted in 

 order to determine the efficiency of the generation ; the results were 

 perfectly satisfactory and showed that up to the last charge the 

 amount of gas involved, though slightly less in proportion, was still 

 quite efficient. Another objection was the solubility of the gas in the 

 diluted acid ; this, though serious in the cold, is of small amount if the 

 liquid be warm ; this warmth is obtained by mixing the acid and water 

 just before use and jacketing the machine with some non-conductor 

 to minimise the loss of heat. This method is found to be accurate in 

 dosage, to give a rapid and uniform generation of gas and does not 

 burn the tents. The apparatus must be kept scrupulously clean and 

 no dirt must be allowed to enter the pump. 



Conor (M.). Les invasions de sauterelles en Afrique Mineure. (Figura- 

 tions et Textes anciens.) [Locust invasions in North Africa. 

 Ancient figures and text references.]— y4rc/i. Instit. Pasteur 

 Tunis, Tunis, ix, no. 3, 1st April 1916, pp. 149-156, 1 plate. 



This paper contains a series of quotations from ancient writers from 

 Herodotus to the Byzantine poet Corippus concerning locust invasions 

 in Northern Africa and their effect. Reproductions of six figures of 

 locusts from mosaics found at El-Djem are given. These are stated 

 to be so accurate that there can be no doubt that the species concerned 

 was Schistocerca peregrina. 



Beeson (C. F. C). Ambrosia Beetles or Pin-Hole and Shot-Hole 

 Borers. (Col., Fam. Ipidae, Platypodidae). — Indian Forester, 

 Allahabad, x\n, no. 4, April 1916, pp. 216-223, 1 plate. 



Ambrosia beetles belonging to the Platypodinae are abundant 

 in India and Burma, while those of the Scolytinae are represented 

 in temperate forests. The majority live in the larval stages on a fungus 



